Four major principles currently underlie U.S. policy on legal permanent immigration: the reunification of families, the admission of immigrants with needed skills, the protection of refugees and asylees, and the diversity of immigrants by country of origin. These principles are embodied in federal law, the Immigration and Nationality Act (INA). The Immigration and Nationality Act Amendments of 1965 replaced the national origins quota system (enacted after World War I) with per-country ceilings, and the statutory provisions regulating legal permanent immigration to the United States were last revised significantly by the Immigration Act of 1990. Despite extensive critiques of the permanent legal immigration system, no consensus exists on the specific direction reforms to the system should take. Some maintain that revising provisions governing legal permanent immigration should be a key component of any major immigration reform proposal, while others support the existing provisions and their underlying rationales. This report on legal permanent immigration may help inform the debate and discussions of policy options that may emerge as Congress considers current immigration proposals. Legal aliens are of three main types: immigrants , nonimmigrants and refugees . As defined in the INA, immigrants are synonymous with lawful permanent residents (LPRs) and refer to foreign nationals who come to live lawfully and permanently in the United States. N onimmigrants —such as tourists, foreign students, diplomats, temporary agricultural workers, exchange visitors, or intracompany business personnel—are admitted for a specific purpose and a temporary period of time. Nonimmigrants must leave the United States before their visas expire, although certain classes of nonimmigrants may adjust to LPR status if they otherwise qualify. Refugees and asylees are people fleeing their countries because of persecution or a well-founded fear of persecution. After one year in refugee status in the United States, refugees must apply to adjust to LPR status. In contrast, asylees may, but are not required to, apply for LPR status after one year. The conditions for the admission of immigrants and refugees are more stringent than for nonimmigrants, and many fewer immigrants than nonimmigrants are admitted each year. Once admitted, however, immigrants are subject to few restrictions; for example, they may accept and change employment, and may apply for U.S. citizenship through the naturalization process, generally after five years. Naturalization is voluntary, and persons may remain as LPRs indefinitely as long as they do not commit a crime or some other act that makes them deportable. Prospective immigrants must maneuver a multi-step process through federal departments and agencies to obtain LPR status. First, petitions for LPR status are filed with U.S. Citizenship and Immigration Services (USCIS) in the Department of Homeland Security (DHS) by the prospective immigrant or by the sponsoring relative or employer in the United States (in the case of family-sponsored or employment-based immigration, respectively). If the prospective LPR is residing abroad or has not established a lawful residence in the United States, the petition is forwarded to the Department of State's (DOS) Bureau of Consular Affairs in the alien's home country after USCIS has approved it. If the prospective immigrant is already legally residing in the United States, USCIS handles most of the process, which the INA refers to as "adjustment of status" because the alien is moving from a temporary status to LPR status. Roughly half of all persons granted LPR status in FY2016—the most recent year for which such data are available—did so by adjusting status. The Consular Affairs officer (when the alien is coming from abroad) or the USCIS adjudicator (when the alien is adjusting status from within the United States) must be satisfied that the alien is entitled to LPR status. These reviews are intended to ensure that prospective immigrants are not ineligible for visas or admission under the grounds for inadmissibility spelled out in the INA. Immigrant admissions and adjustments to LPR status are subject to complex numerical limits and preference categories that give priority for admission on the basis of family relationships, needed skills, and geographic diversity. In addition, immigrants who enter through the family-sponsored and employment based preference categories are subject to a 7% per-country cap (see " Per-country Ceilings " below). Numerical limits on immigration combined with the per-country cap for some categories has resulted in a sizable "visa queue" of foreign nationals with approved immigration petitions who must wait until a numerically limited visa becomes available before they can immigrate permanently to the United States (see " The Visa Queue " below). The INA provides for a permanent annual worldwide level of 675,000 LPRs comprising three components: 1. family-sponsored immigrants (480,000 plus certain unused employment-based preference numbers from the prior year), made up of two groups: a. immediate relatives of U.S. citizens and b. family-sponsored preference immigrants; 1. employ ment-based preference immigrants (140,000 plus certain unused family preference numbers from the prior year); and 2. diversity immigrants (55,000). Despite the numerical limits, the annual worldwide level is flexible, and the INA permits certain LPR categories to exceed the limits. For example, although the INA places a limit of 480,000 on family-sponsored immigrants, some refer to that limit as a "permeable cap" because immediate relatives of U.S. citizens are not numerically limited. The annual level of family-sponsored preference immigrants is determined as follows: 480,000 (the total family-sponsored immigration level), minus the number of immediate relatives granted LPR status in the prior year, minus the number of aliens paroled into the United States for at least a year, plus (when available) the number of unused employment preference immigrant from the prior year. As a result, the actual number of immigrants who receive LPR status varies from year to year according to the prior year's number of immediate relative immigrants, parolees, and unused employment-based preference immigrant visas that roll over. Under the INA, the annual level of family preference immigrants may not fall below 226,000. If the number of immediate relatives of U.S. citizens admitted in the previous year happens to fall below 254,000 (the difference between 480,000 for all family-sponsored immigrants and 226,000 for family-sponsored preference immigrants), then family-sponsored preference immigrants may exceed 226,000 by that amount. However, since FY1996, annual admissions of immediate relatives of U.S. citizens have exceeded 254,000 each year, ranging from a low of 258,584 immigrants in FY1999 to a peak of 580,348 immigrants in FY2006; in FY2016 they numbered 566,706. Consequently, the annual limit for family-sponsored preference immigrants has effectively remained at 226,000 for the past two decades. The United States also gives LPR status to persons admitted as refugees and persons who are granted asylum. Refugees and asylees can apply to adjust to LPR status after one year in refugee/asylee status in the United States. Refugees and asylees are exempt from statutory numerical limits. As mentioned above, numerically-limited preference immigrants who enter through the family-sponsored and employment based preference categories are limited by a 7% per-country cap. The per-country level is not a quota or set aside for individual countries, as each of the 195 countries in the world could not receive 7% of the specified limit. As the State Department describes: "(T)he country limitation serves to avoid monopolization of virtually all the annual limitation by applicants from only a few countries. This limitation is not a quota to which any particular country is entitled, however." Congress has enacted two important exceptions to the per-country ceilings. The first exception allows 75% of the visas allocated to the 2 nd family preference category (2A) of spouses and children of LPRs to be exempt from the per-country ceiling (see Table 1 for family preference categories). The second exception allows the 7% per-country ceiling for employment-based immigrants to be surpassed for individual countries that are oversubscribed if visas are available within the 140,000 worldwide limit for employment-based preferences. The impact of these revisions to the per-country ceilings is discussed later in this report. As noted, family-sponsored and employment-based preference category immigrants are numerically limited. Both types of immigrants are subdivided into five categories. Within each family and employment preference category, the INA further allocates the number of people who can receive LPR status each year. The five family preference categories are based broadly upon a hierarchy of family relationships to U.S. citizens and LPRs. Among the five employment preference categories, the first three are based broadly upon a hierarchy of professional accomplishments and skills needed by U.S. employers ( Table 1 ). The fourth category includes 13 sub-categories of "special immigrants," including religious workers, employees of the U.S. government abroad, and juvenile court dependents. As part of the Immigration Act of 1990, Congress added a fifth preference employment-based category that allows foreign investors to acquire LPR status ("EB-5 immigrant investors"). For this preference category, the INA allocates up to 10,000 admissions annually and generally requires a minimum $1 million investment and employment of at least 10 U.S. workers. Less capital is required for aliens who invest in "Targeted Employment Areas" (TEAs), which include rural areas (as defined by the Office of Management and Budget) or areas experiencing unemployment at 150% of the national average. Employers seeking to hire prospective immigrants through the second and third employment-based preference categories must petition the U.S. Department of Labor (DOL) to obtain a labor certification on behalf of the alien. Prospective immigrants must demonstrate that they meet the qualifications for both the particular job and the preference category. If DOL determines that a labor shortage exists in the occupation for which a petition is filed, it will issue a labor certification. If DOL determines that such a labor shortage does not exist, the employer must submit evidence of extensive recruitment efforts that have failed in order to obtain certification. Table 1 summarizes the preference system for family-sponsored and employment-based immigrants. In most instances unused numbers roll down to the next preference category. Employment-based LPR allocations not used in a given year rollover to the family preference categories the following year, and vice versa for unused family-sponsored LPR allocations. The diversity immigrant visa fosters legal immigration from countries that send relatively few immigrants to the United States. Each year, 50,000 visas are made available to selected natives of countries from which immigrant admissions totaled less than 50,000 over the preceding five years. Since the visa's inception in the early 1990s, the regional distribution of diversity lottery immigrants has shifted from Western European to African and Eastern European countries. To be eligible for a diversity immigrant visa, foreign nationals must have a high school education or two years of work experience within the past five years in an occupation that requires at least two years of training or experience to perform. Applicants are selected by lottery whose winners must also meet the standard eligibility criteria required for most immigrants. Several other pathways apart from family-sponsored and employment-based immigrants allow persons to acquire LPR status. They range from aliens in removal (i.e., deportation) proceedings who are granted LPR status by an immigration judge, victims of crime and human trafficking, and refugees and asylees who adjust to LPR status. Table 2 summarizes these major pathways and any related numerical limitations. Immigration to the United States ( Figure 1 ) is determined by many factors apart from U.S. immigration laws. Push factors from immigrant-sending countries include civil wars, political unrest, economic deprivation, limited job opportunities, and catastrophic natural disasters. Pull factors from the United States include relatively strong employment prospects, opportunities to reunite with family members, and quality of life considerations. A corollary factor is the extent to which aliens can migrate to other countries offering circumstances and opportunities comparable to, or better than, the United States. U.S. immigration, which experienced several peaks between the late 19 th and early 20 th Centuries declined considerably as the result of the Great Depression and World War II. The annual number of persons acquiring LPR status who were admitted from abroad or adjusting status from within the United States rose gradually after World War II and continued steadily for three decades, partly as the result of war refugee admissions as well as a growing U.S. economy. After 1980, immigration growth occurred for a number of reasons. First, the Immigration Reform and Control Act of 1986 (IRCA, P.L. 99-603 ) legalized 2.7 million aliens who were residing in the United States without authorization. These newly legalized individuals were then eligible to sponsor other family members, either as LPRs or, for those who subsequently naturalized, as U.S. citizens. Second, the Immigration Act of 1990 ( P.L. 101-649 ) increased the ceiling on employment-based preference immigration and included a provision allowing unused employment-based preference visas to be made available the following year for family-sponsored preference immigration and vice versa for unused family-sponsored preference visas. Third, following the enactment of the Refugee Act of 1980 ( P.L. 96-212 ), the number of refugees admitted increased from 718,000 for the 15-year period between 1966 and 1980 to 1.6 million between 1981 and 1995. In any given period of U.S. history, a handful of countries have dominated the flow of immigrants, but the dominant countries have changed over time. Figure 2 presents the countries from where the most individuals emigrated and together comprised at least half of all immigrants for selected decades. The figure illustrates two points. First, while immigration at the start of the 20 st century was dominated by three or four countries, immigration at the start of the 21 st century originated from a much broader set of countries. Second, these data suggest that the per-country ceilings established by the Immigration and Nationality Act Amendments of 1965 had a considerable impact on this shift in country-of-origin composition. Figure 2 also illustrates the change in geographic origin of U.S. immigration. Most immigrants during the early 20 th century originated from European countries, such as Germany, Italy, Austria-Hungary, and the United Kingdom. Mexico has been a top sending country for most of the 20 th century and into the 21 st century. Most immigrants in more recent decades originate from Western Hemisphere countries such as the Dominican Republic, Cuba, Haiti, Jamaica, and Colombia, and Asian countries including China, India, the Philippines, Vietnam, and South Korea. In FY2016, approximately 1.2 million aliens became LPRs, either by being admitted as such upon arrival to the United States from overseas, or by adjusting to LPR status from a nonimmigrant status while in the United States ( Figure 3 ) . Of this total, just over two-thirds acquired LPR status as family-sponsored immigrants . Employment-based immigrants (12%) and refugees and asylees (13%) make up another quarter, and diversity immigrants (4%), and all other classes of immigrants (3%) make up the remainder. Immediate relatives of U.S. citizens, who are not numerically limited by the INA, accounted for 48% of all LPRs granted in 2016. This portion of all LPRs can be further broken down by relationship to the U.S. citizen: spouses made up 26%, parents made up 15%, and children (including adopted orphans) made up 7%. In FY2016, Mexico was the source country of 15% of LPRs who were admitted or adjusted status. Other top countries were China (7%), Cuba (6%), India (5%), and the Dominican Republic (5%). These five countries made up 37% of all LPRs who were admitted or who adjusted status in FY2016. Similarly, the leading regions of birth for LPRs in FY2016 were Asia (37%), Mexico and Central America (20%), and the Caribbean (15%), together accounting for almost three-fourths of all LPRs. In FY2016, 565,427 aliens (48%) adjusted to LPR status from within the United States, while 618,078 (52%) received visas issued abroad from DOS Consular Affairs, arrived from overseas, and were admitted as LPRs . Over the last two decades, the percentage of all LPRs adjusting status each year has ranged from 38% in FY1999 to 66% in FY2005. In FY2016, most employment-based immigrants (82%) adjusted to LPR status from within the United States. Close to half (45%) of immediate relatives of U.S. citizens also did so that year, in contrast with less than 10% of family-preference immigrants. The pool of people eligible to immigrate to the United States as LPRs each year typically exceeds the worldwide level set by U.S. immigration law. At the end of each fiscal year, the Department of State (DOS) publishes a tabulation of immigrant petitions that have been approved by USCIS and forwarded to DOS's National Visa Center. These published figures do not constitute a backlog of petitions to be processed; they represent persons who have been approved as family-sponsored or employment-based immigrants who cannot yet immigrate to the United States due to numerical limits in the INA. The National Visa Center caseload drives the priority dates published in the monthly Visa Bulletin . Family-sponsored preference immigrants dominated the queue of 4.06 million approved LPR visa petitions pending with the National Visa Center at the end of FY2017 ( Figure 4 ). Over half (58%) of all approved petitions pending were 4 th preference siblings of U.S. citizens, and one-quarter (25%) were 1 st preference unmarried adult children and 3 rd preference married adult children of U.S. citizens. Second preference family members of LPRs totaled 14% of the queue. Figure 4 indicates that employment-based preference immigrants accounted for 3% of the 4.06 million LPR visas pending with the National Visa Center as of November 1, 2017. This figure of 112,189 reflected not only principal applicants or petition beneficiaries, but also their spouses and children entitled to derivative status under the INA). In addition to the visa queue that has accumulated at DOS's National Visa Center and which is described in an annual DOS report, there is also a queue of petitions that have been received by USCIS and are pending completed processing. USCIS performance data suggest that USCIS has not yet forwarded a substantial portion of its LPR caseload to the DOS National Visa Center. This queue includes family-sponsored, employment-based, and humanitarian (e.g., refugee, asylum) petitions for LPR status. Family-sponsored and employment-based preference visas are issued to eligible immigrants in the order in which petitions are filed. In addition, spouses and children of prospective LPRs are entitled to the same status and order of consideration as the person qualifying as the principal LPR, if they are accompanying or "following to join" (referred to as derivative status). When visa demand exceeds the numerical limits, visas are allocated according to the preference system detailed in Table 1 for the "oversubscribed" foreign state or dependent area. Table 3 presents information from a recent Visa Bulletin published monthly by the Department of State for all five family-sponsored preference categories. It indicates that, as of February 9, 2018 (the date when the March Visa Bulletin was published), relatives of U.S. citizens and LPRs who fell into all five of these categories and who had approved immigration petitions were waiting for a visa to become available. As such, it reflects the consequences of both numerical limits for family-sponsored and employment-based preference immigrants as well as the 7% per-country cap on those LPR categories. According to the March 2018 Visa Bulletin ( Table 3 ), DOS was processing visa petitions, as of February 9, 2018, for unmarried adult sons and daughters of U.S. citizens (1 st preference) from India whose immigration petitions were submitted to USCIS on March 22, 2011. Depending on the country of origin, persons in this category who had submitted petitions even earlier were also being processed for visas. Likewise, as of February 9, 2018, DOS was processing visa petitions for married adult sons and daughters of U.S. citizens from China (3 rd preference) whose immigration petitions were submitted to USCIS more than 12 years ago (December 15, 2005). Depending on the country of origin, persons in this category who had submitted petitions even earlier were also being processed for visas. Brothers and sisters of U.S. citizens (4 th preference) could expect to wait over 13 years, with considerably longer waits for siblings from Mexico and the Philippines. DOS consular officers, as of February 9, 2018, were adjudicating visa petitions of brothers and sisters of U.S. citizens from the Philippines who had filed immigration petitions over 23 years ago. In contrast, spouses and minor children of LPRs (category F2A in Table 3 ) for all countries had the most recent priority date of March 22, 2016, indicating that DOS consular officers were adjudicating visa petitions submitted approximately two years ago. Table 4 presents information from the March 2018 Visa Bulletin for the five employment preference categories. It indicates that, as of February 9, 2018, categories for all worker visas were current. However, workers applying to emigrate from countries that send large numbers of employment-based immigrants to the United States faced waiting times for specific categories. For example, those seeking advanced degree visas from China and India had December 8, 2013, and December 15, 2008, priority dates, respectively. Visas granted for professional and skilled workers were current, except for workers from China, India and the Philippines, who faced waiting times. Some posit that revising the system of permanent legal immigration should be a major component of any immigration reform proposal. In recent years, Congress has considered proposals to alter the legal immigration system—either with a comprehensive approach or with incremental revisions aimed at strategic changes. Those favoring expanded immigration typically advocate for specific changes. Some favor a significant reallocation of the visa categories or a substantial increase in legal immigration to satisfy the desire of U.S. families to reunite with their relatives still abroad and to meet the labor force needs of employers hiring foreign workers. Others favor a reallocation toward employment-based immigration to help U.S. employers compete for the "best and the brightest," including foreign professional workers in science, technology, engineering, or mathematics (STEM) fields. Proponents of family-sponsored migration maintain that any proposal to increase immigration levels generally should also include the option of additional family-sponsored visas to reduce wait times—currently up to years or decades—for those already "in the queue." Those who favor reduced immigration contend that family-sponsored immigration permits relatively large numbers of foreign nationals to permanently settle in the United States without regard to their skill, education levels, or potential contribution to the U.S. economy. Some argue that family-sponsored immigration should be limited to immediate relatives of U.S. citizens and LPRs. Others favor revising employment-based immigration so that immigrants are selected on the basis of "merit-based" criteria (e.g., educational attainment, employment in a high demand field, English language skills, age) rather than largely being sponsored by employers under the current system. Many in Congress also support eliminating the Diversity Immigrant Visa which they contend poses security risks and requires relatively little in terms of skill and education requirements.

Summary: Four major principles currently underlie U.S. policy on legal permanent immigration: the reunification of families, the admission of immigrants with needed skills, the protection of refugees and asylees, and the diversity of immigrants by country of origin. These principles are embodied in the Immigration and Nationality Act (INA) and are reflected in different components of permanent immigration. Family reunification occurs primarily through family-sponsored immigration. U.S. labor market contribution occurs through employment-based immigration. Humanitarian assistance occurs primarily through the U.S. refugee and asylee programs. Origin-country diversity is addressed through the Diversity Immigrant Visa. In addition to the primary components of permanent immigration discussed above, there are several other pathways to lawful permanent resident (LPR) status, though they account for relatively few immigrants. The most prominent among these are cancellation of removal for aliens in removal proceedings, U nonimmigrant visas for alien crime victims who assist law enforcement agencies, and T status for alien victims of human trafficking. The pool of people eligible to immigrate to the United States as LPRs each year typically exceeds numerical limits established by the INA for most immigrant pathways. In an effort to process the demand for LPR visas fairly and in accordance with the national interest, the INA imposes a complex set of numerical limits and preference categories within major immigrant pathways that admit LPRs to the United States on the basis of family relationships, needed skills, and geographic diversity. The INA limits worldwide permanent immigration to 675,000 persons annually: 480,000 family-sponsored immigrants, made up of family-sponsored immediate relatives of U.S. citizens ("immediate relatives"), and a set of ordered family-sponsored preference immigrants ("preference immigrants"); 140,000 employment-based immigrants; and 55,000 diversity visa immigrants. This worldwide limit, however, is referred to as a "permeable cap," because certain categories of LPRs are not subject to numerical limitations. These include immediate relatives of U.S. citizens within the INA's family-sponsored immigration provisions, as well as refugees whose number is determined by the President in consultation with Congress. In addition, the number of persons granted asylum is not numerically constrained. Consequently, the number of persons receiving LPR status each year regularly exceeds the INA's statutory worldwide level for permanent immigration. The INA further specifies that countries are held to a numerical limit of 7% of the annual worldwide level of family-sponsored and employment-based immigrants, known as the per-country limit or country cap. The cap is intended to prevent one or just a few countries from dominating immigrant flows. In FY2016, almost 1.2 million aliens became LPRs. Of this total, 68% became LPRs through family-sponsored provisions of the INA. Other major LPR categories included refugees and asylees (13%), employment-based immigrants (12%), and diversity visa immigrants (4%). While 618,078 LPRs (52%) in FY2016 were granted LPR status upon their admission to the United States from abroad, 565,427 (48%) adjusted to LPR status from a temporary (i.e., nonimmigrant) status from within the United States. In FY2016, Mexico accounted for the largest proportion (15%) of LPRs who were admitted from abroad or adjusted status from within the United States. Other top immigrant source countries included China (7%), Cuba (6%), India (5%), and the Dominican Republic (5%). At the start of FY2018, approximately 4.1 million approved LPR visa petitions—almost all family-sponsored petitions—were pending with the Department of State's National Visa Center because of the numerical limits in the INA. Approximate wait times for numerically limited family and employment preference visas range widely depending on the specific preference category and country of origin. Prospective family-sponsored immigrants from China, Mexico, India and the Philippines have the most substantial wait times before a visa is scheduled to become available to them. Some have advocated for a significant reallocation of the visa categories or a substantial increase in legal immigration to satisfy the desire of U.S. families to reunite with their relatives abroad and to meet the labor force needs of U.S. employers. Proponents of family-sponsored migration often maintain that proposals to increase immigration should include additional family-sponsored visas to more quickly reunify families by reducing wait times—currently up to years and decades—for those already "in the queue." Those who favor reduced immigration have supported proposals to limit family-sponsored LPRs to the immediate relatives of U.S. citizens, to confine employment-based LPRs to highly skilled workers, to admit employment-based immigrants using some type of merit-based system, and to eliminate the diversity visa. Four major principles currently underlie U.S. policy on legal permanent immigration: the reunification of families, the admission of immigrants with needed skills, the protection of refugees and asylees, and the diversity of immigrants by country of origin. These principles are embodied in the Immigration and Nationality Act (INA) and are reflected in different components of permanent immigration. Family reunification occurs primarily through family-sponsored immigration. U.S. labor market contribution occurs through employment-based immigration. Humanitarian assistance occurs primarily through the U.S. refugee and asylee programs. Origin-country diversity is addressed through the Diversity Immigrant Visa. In addition to the primary components of permanent immigration discussed above, there are several other pathways to lawful permanent resident (LPR) status, though they account for relatively few immigrants. The most prominent among these are cancellation of removal for aliens in removal proceedings, U nonimmigrant visas for alien crime victims who assist law enforcement agencies, and T status for alien victims of human trafficking. The pool of people eligible to immigrate to the United States as LPRs each year typically exceeds numerical limits established by the INA for most immigrant pathways. In an effort to process the demand for LPR visas fairly and in accordance with the national interest, the INA imposes a complex set of numerical limits and preference categories within major immigrant pathways that admit LPRs to the United States on the basis of family relationships, needed skills, and geographic diversity. The INA limits worldwide permanent immigration to 675,000 persons annually: 480,000 family-sponsored immigrants, made up of family-sponsored immediate relatives of U.S. citizens ("immediate relatives"), and a set of ordered family-sponsored preference immigrants ("preference immigrants"); 140,000 employment-based immigrants; and 55,000 diversity visa immigrants. This worldwide limit, however, is referred to as a "permeable cap," because certain categories of LPRs are not subject to numerical limitations. These include immediate relatives of U.S. citizens within the INA's family-sponsored immigration provisions, as well as refugees whose number is determined by the President in consultation with Congress. In addition, the number of persons granted asylum is not numerically constrained. Consequently, the number of persons receiving LPR status each year regularly exceeds the INA's statutory worldwide level for permanent immigration. The INA further specifies that countries are held to a numerical limit of 7% of the annual worldwide level of family-sponsored and employment-based immigrants, known as the per-country limit or country cap. The cap is intended to prevent one or just a few countries from dominating immigrant flows. In FY2016, almost 1.2 million aliens became LPRs. Of this total, 68% became LPRs through family-sponsored provisions of the INA. Other major LPR categories included refugees and asylees (13%), employment-based immigrants (12%), and diversity visa immigrants (4%). While 618,078 LPRs (52%) in FY2016 were granted LPR status upon their admission to the United States from abroad, 565,427 (48%) adjusted to LPR status from a temporary (i.e., nonimmigrant) status from within the United States. In FY2016, Mexico accounted for the largest proportion (15%) of LPRs who were admitted from abroad or adjusted status from within the United States. Other top immigrant source countries included China (7%), Cuba (6%), India (5%), and the Dominican Republic (5%). At the start of FY2018, approximately 4.1 million approved LPR visa petitions—almost all family-sponsored petitions—were pending with the Department of State's National Visa Center because of the numerical limits in the INA. Approximate wait times for numerically limited family and employment preference visas range widely depending on the specific preference category and country of origin. Prospective family-sponsored immigrants from China, Mexico, India and the Philippines have the most substantial wait times before a visa is scheduled to become available to them. Some have advocated for a significant reallocation of the visa categories or a substantial increase in legal immigration to satisfy the desire of U.S. families to reunite with their relatives abroad and to meet the labor force needs of U.S. employers. Proponents of family-sponsored migration often maintain that proposals to increase immigration should include additional family-sponsored visas to more quickly reunify families by reducing wait times—currently up to years and decades—for those already "in the queue." Those who favor reduced immigration have supported proposals to limit family-sponsored LPRs to the immediate relatives of U.S. citizens, to confine employment-based LPRs to highly skilled workers, to admit employment-based immigrants using some type of merit-based system, and to eliminate the diversity visa.