Question: How many US citizens are living outside of US?

American diaspora



The American diaspora or overseas Americans refers to the population of United States citizens who relocate, temporarily or permanently, to foreign countries.
Number of U.S. citizens living abroad
There are no exact figures on how many Americans live abroad. In 1999, a State Department estimate suggested that the number may be between 3 million and 6 million.[47][48] In 2016, the agency estimated 9 million U.S. citizens were living abroad.[1] However, these numbers are highly open to dispute as they often are unverified and can change rapidly.[49] The United States Census Bureau does not count Americans abroad and individual American embassies offer only rough estimates, which makes the U. S. the only developed country that does not even attempt a formal enumeration of expatriate citizens. The State Department does not release what statistics it may have, citing "security reasons."[47]
One reasonably "hard" indicator of the U.S. citizen population overseas is offered by the fact that often when they have a child abroad, they obtain a Consular Report of Birth Abroad from a US consulate as a proof of the child's U.S. citizenship. The Bureau of Consular Affairs reports issuing 503,585 such documents over the decade 2000–2009. Based on this, and on some assumptions about the family composition and birth rates, some authors estimate the US civilian population overseas as between 3.6 and 4.3 million.[50]
Sizes of certain subsets of US citizens living abroad can be estimated based on statistics published by the Internal Revenue Service. US Citizens are generally liable for US income tax even if they reside overseas; however, if they receive earned income (wages, salaries, etc.) while residing in a foreign country, they can exclude an amount of foreign earned income from the US taxation or receive credit for foreign taxes paid. The IRS reported that almost 335,000 tax returns with such a foreign-earned income exclusion form were received in 2006.[51] This imposes a lower (and very imprecise) bound on the number of US citizens who were living and working in foreign countries at the time.
In the same tax year, almost 969,000 US taxpayers reported having paid foreign tax on "general limitation income" (i.e., income other than interest, dividends, and other "passive income") from foreign sources on their foreign tax credit forms.[51]  Of course, not all of these were actually residing abroad full-time.
Reasons for emigrating
There are a wide range of reasons for which Americans might emigrate from the country. While some emigrate for economic reasons, the United States' position as an affluent country and one of many immigrants means that many leave for a chance to experience other parts of the world, to return to their country of origin, for religious reasons, such as missionary work, or to escape policies of the American government.[52] Americans do not easily have access to any foreign country for the purpose of permanent residence (with certain exceptions such as Jews emigrating to Israel), so the American diaspora is relatively small in comparison to the total American population.
With the ongoing problems with the American economy, and increase in economic opportunities for skilled laborers in emerging markets, economic opportunities are increasingly driving migration abroad, both for native-born Americans[53] and naturalized immigrants returning to their home country.
Common reasons for living abroad are marriage/partnership, study, employment, and retirement. Since children born in the United States to non-citizens are granted U.S. citizenship, children born to migrant workers, temporary foreign employees on visas, or international students are U.S. citizens, and when they return to their countries of origin, they are also considered to be U.S. citizens living abroad. They are sometimes called "accidental Americans".[54]
History
Due to the flow of people back and forth between Britain and the colonies, and America and the Caribbean, there has been an American diaspora of a sort since before the United States was founded. During the American Revolutionary War, a number of American Loyalists relocated to other countries, chiefly Canada and Great Britain. Residence in countries outside the British Empire was unusual, and usually limited to the well to do, such as Benjamin Franklin, who was able to self-finance his trip to Paris as an American diplomat.
19th century
Thanks to the increase of whalers and clipper ships, Americans began to travel all over the world for commercial reasons.
The early 19th century also saw the beginning of overseas missionary activity, such as with Adoniram Judson in Burma.
The middle of the 19th century saw the immigration of many New Englanders to Hawaii, as missionaries for the Congregational Church, and as traders and whalers. The American population eventually overthrew the government of Hawaii, leading to its annexation by the United States.
During this time former slaves also migrated to Liberia, becoming the Americo-Liberians, who dominated the country for most of its history.
Also, due to the American invasion. Many Americans became immigrants to the Philippines when it was a colony after America's victory in the Philippine–American War.
In Asia, the American government made efforts to secure special privileges for its citizens. This began with the Treaty of Wanghia in China in 1844.  It was followed by the expedition of Commodore Perry to Japan 10 years later, and the United States–Korea Treaty of 1882. American traders began to settle in those countries.
Early 20th century
Cecil Rhodes created the Rhodes Scholarship in 1902 to encourage greater cooperation between the United States, the British Empire, and Germany by allowing students to study abroad.
Interwar period

In the period between the First and Second World Wars, many Americans, particularly writers such as Ernest Hemingway, Gertrude Stein, and Ezra Pound, migrated to Europe to take part in the cultural scene.
European cities like Amsterdam, Berlin, Copenhagen, Paris, Prague, Rome, Stockholm, and Vienna came to host a large number of Americans.  Many Americans also participated in the Spanish Civil War in Spain while they lived in Madrid and elsewhere.
Other Americans returned home to the countries of their origin, including the parents of American author/illustrator Eric Carle, who returned to Germany. Thousands of Japanese Americans were unable to return to the United States, after the Attack on Pearl Harbor.[55]
Cold War
During the Cold War, Americans became a permanent fixture in many countries with large populations of American soldiers, such as West Germany and South Korea.
The Cold War also saw the development of government programs to encourage young Americans to go abroad.  The Fulbright Program was established in 1946 to encourage cultural exchange, and the Peace Corps was created in 1961 both to encourage cultural exchange and a civic spirit of volunteerism.
With the formation of the state of Israel, over 100,000 Jews made Aliyah to the holy land, where they played a role in the creation of the state.  Other Americans traveled to countries like Lebanon, again to take place in the cultural scene.
During the Vietnam War, about 100,000 American men went abroad to avoid conscription, 90% of them going to Canada.[56] European nations, including neutral states like Denmark, Norway, Sweden, and Switzerland, offered asylum to thousands of American expatriates who refused to fight.
A small number of Americans abandoned the country for political reasons, defecting to the Soviet Union, Cuba, or other countries, such as Miguel d'Escoto Brockmann, current Libyan nominee as UN ambassador, and sixties radicals such as Joanne Chesimard, Pete O'Neal, Eldridge Cleaver, and Stokely Carmichael.
During this period Americans continued to travel abroad for religious reasons, such as Richard James, inventor of the Slinky, who went to Bolivia with the Wycliffe Bible Translators, and the Peoples Temple establishment of Jonestown in Guyana.
After the Cold War
The opening of Eastern Europe, Central Europe, and Central Asia after the Cold War provided new opportunities for American businesspeople. Additionally, with the global dominance of America in the world economy, the ESL industry continued to grow, especially in new and emerging markets. Many Americans also take a year abroad during college, and some return to the country after graduation.
Iraq War deserters sought refuge mostly in Canada and Europe, and NSA whistleblower Edward Snowden escaped to  Russia.[57][58]
Increasing numbers of Americans are retiring abroad due to financial setbacks resulting from the 2008 financial crisis.[59]
Young Americans facing a tough job market due to the recession are also increasingly open to working abroad.[60]
Issues
One of the biggest issues with the American diaspora is the issue of double taxation. Unlike most developed nations, the United States taxes its citizens even when they live overseas. The Foreign Earned Income Exclusion mitigates double taxation on wage income, but the Internal Revenue Code treats ordinary foreign savings plans held by residents of foreign countries as if they were offshore tax avoidance instruments and requires extensive asset reporting, resulting in significant costs for Americans at all income levels to comply with filing requirements even when they owe no tax.[47][61][62] Even Canada's Registered Disability Savings Plan falls under such reporting requirements.[63] The most prominent piece of legislation which has attracted the ire of Americans abroad is the Foreign Account Tax Compliance Act (FATCA). Disadvantages stemming from FATCA, such as hindering career advancement overseas, may decrease the number of Americans in the diaspora in future years. The problem is so severe that some Americans have addressed it by renouncing or relinquishing their American citizenship.[64] Since 2013, the number of people giving up US citizenship has risen to a new record each year, with an unprecedented 5,411 in 2016. This is up 26 percent from the 4,279 renunciations in 2015.[65][66][67]
See also
Emigration from the United States
American-Canadian
Americo-Liberian
American settlement in the Philippines
Lost Generation
Mexicans of American descent
Confederados of Brazil
Taxation of non resident Americans 
American Citizens Abroad
Taxation of United States persons
International taxation of Americans
Renunciation of United States citizenship
Samana English



, Esquire, 26 September 2008.
Jones, Chris.  . Esquire, 23 September 2008.
Sappho, Paul. , Harvard Business Review, 2009.
Sullivan, Andrew.  The Atlantic, 29 September 2009.
, The Economist, 14 April 2011.
William Curtis Donovan. , 1 October 2008.