Question: When did the country of the groups from The Sing-Off not from the U.S. become a commonwealth of the U.S.?

full_context: Document 1: A cappella: In July 1943, as a result of the American Federation of Musicians boycott of US recording studios, the a cappella vocal group The Song Spinners had a best-seller with "Comin' In On A Wing And A Prayer". In the 1950s several recording groups, notably The Hi-Los and the Four Freshmen, introduced complex jazz harmonies to a cappella performances. The King's Singers are credited with promoting interest in small-group a cappella performances in the 1960s. In 1983 an a cappella group known as The Flying Pickets had a Christmas 'number one' in the UK with a cover of Yazoo's (known in the US as Yaz) "Only You". A cappella music attained renewed prominence from the late 1980s onward, spurred by the success of Top 40 recordings by artists such as The Manhattan Transfer, Bobby McFerrin, Huey Lewis and the News, All-4-One, The Nylons, Backstreet Boys and Boyz II Men.[citation needed]
Document 2: Puerto Rico: Puerto Ricans are by law citizens of the United States and may move freely between the island and the mainland. As it is not a state, Puerto Rico does not have a vote in the United States Congress, which governs the territory with full jurisdiction under the Puerto Rico Federal Relations Act of 1950. However, Puerto Rico does have one non-voting member of the House called a Resident Commissioner. As residents of a U.S. territory, American citizens in Puerto Rico are disenfranchised at the national level and do not vote for president and vice president of the United States, and do not pay federal income tax on Puerto Rican income. Like other territories and the District of Columbia, Puerto Rico does not have U.S. senators. Congress approved a local constitution in 1952, allowing U.S. citizens on the territory to elect a governor. A 2012 referendum showed a majority (54% of those who voted) disagreed with ``the present form of territorial status ''. A second question asking about a new model, had full statehood the preferred option among those who voted for a change of status, although a significant number of people did not answer the second question of the referendum. A fifth referendum was held on June 11, 2017, with`` Statehood'' and ``Independence / Free Association ''initially as the only available choices. At the recommendation of the Department of Justice, an option for the`` current territorial status'' was added. The referendum showed an overwhelming support for statehood, with 97.18% voting for it, although the voter turnout had a historically low figure of only 22.99% of the registered voters casting their ballots.
Document 3: A cappella: Increased interest in modern a cappella (particularly collegiate a cappella) can be seen in the growth of awards such as the Contemporary A Cappella Recording Awards (overseen by the Contemporary A Cappella Society) and competitions such as the International Championship of Collegiate A Cappella for college groups and the Harmony Sweepstakes for all groups. In December 2009, a new television competition series called The Sing-Off aired on NBC. The show featured eight a cappella groups from the United States and Puerto Rico vying for the prize of $100,000 and a recording contract with Epic Records/Sony Music. The show was judged by Ben Folds, Shawn Stockman, and Nicole Scherzinger and was won by an all-male group from Puerto Rico called Nota. The show returned for a second and third season, won by Committed and Pentatonix, respectively.
Document 4: A cappella: Contemporary a cappella includes many vocal groups and bands who add vocal percussion or beatboxing to create a pop/rock/gospel sound, in some cases very similar to bands with instruments. Examples of such professional groups include Straight No Chaser, Pentatonix, The House Jacks, Rockapella, Mosaic, and M-pact. There also remains a strong a cappella presence within Christian music, as some denominations purposefully do not use instruments during worship. Examples of such groups are Take 6, Glad and Acappella. Arrangements of popular music for small a cappella ensembles typically include one voice singing the lead melody, one singing a rhythmic bass line, and the remaining voices contributing chordal or polyphonic accompaniment.
Document 5: Catalan language: These territories are sometimes referred to as the Països Catalans (Catalan Countries), a denomination based on cultural affinity and common heritage, that has also had a subsequent political interpretation but no official status. Various interpretations of the term may include some or all of these regions.
Document 6: Washington University in St. Louis: Washington University has a large number of student-run musical groups on campus, including 12 official a cappella groups. The Pikers, an all-male group, is the oldest such group on campus. The Greenleafs, an all-female group is the oldest (and only) female group on campus. The Mosaic Whispers, founded in 1991, is the oldest co-ed group on campus. They have produced 9 albums and have appeared on a number of compilation albums, including Ben Folds' Ben Folds Presents: University A Cappella! The Amateurs, who also appeared on this album, is another co-ed a cappella group on campus, founded in 1991. They have recorded seven albums and toured extensively. After Dark is a co-ed a cappella group founded in 2001. It has released three albums and has won several Contemporary A Capella Recording (CARA) awards. In 2008 the group performed on MSNBC during coverage of the vice presidential debate with specially written songs about Joe Biden and Sarah Palin. The Ghost Lights, founded in 2010, is the campus's newest and only Broadway, Movies, and Television soundtrack group. They have performed multiple philanthropic concerts in the greater St. Louis area and were honored in November 2010 with the opportunity to perform for Nobel Laureate Douglass North at his birthday celebration.
Document 7: A cappella: Barbershop music is one of several uniquely American art forms. The earliest reports of this style of a cappella music involved African Americans. The earliest documented quartets all began in barbershops. In 1938, the first formal men's barbershop organization was formed, known as the Society for the Preservation and Encouragement of Barber Shop Quartet Singing in America (S.P.E.B.S.Q.S.A), and in 2004 rebranded itself and officially changed its public name to the Barbershop Harmony Society (BHS). Today the BHS has over 22,000 members in approximately 800 chapters across the United States, and the barbershop style has spread around the world with organizations in many other countries. The Barbershop Harmony Society provides a highly organized competition structure for a cappella quartets and choruses singing in the barbershop style.
Document 8: 51st state: Puerto Rico is designated in its constitution as the "Commonwealth of Puerto Rico". The Constitution of Puerto Rico which became effective in 1952 adopted the name of Estado Libre Asociado (literally translated as "Free Associated State"), officially translated into English as Commonwealth, for its body politic. The island is under the jurisdiction of the Territorial Clause of the U.S. Constitution, which has led to doubts about the finality of the Commonwealth status for Puerto Rico. In addition, all people born in Puerto Rico become citizens of the U.S. at birth (under provisions of the Jones–Shafroth Act in 1917), but citizens residing in Puerto Rico cannot vote for president nor for full members of either house of Congress. Statehood would grant island residents full voting rights at the Federal level. The Puerto Rico Democracy Act (H.R. 2499) was approved on April 29, 2010, by the United States House of Representatives 223–169, but was not approved by the Senate before the end of the 111th Congress. It would have provided for a federally sanctioned self-determination process for the people of Puerto Rico. This act would provide for referendums to be held in Puerto Rico to determine the island's ultimate political status. It had also been introduced in 2007.
Document 9: Puerto Rico: Puerto Rico (Spanish for ``Rich Port ''), officially the Commonwealth of Puerto Rico (Spanish: Estado Libre Asociado de Puerto Rico, lit.`` Free Associated State of Puerto Rico'') and briefly called Porto Rico, is an unincorporated territory of the United States located in the northeast Caribbean Sea, approximately 1,000 miles (1,600 km) southeast of Miami, Florida.
Document 10: Grammy Award for Best Contemporary Performance by a Chorus: The Grammy Award for Best Contemporary Performance by a Chorus was awarded in 1969 (as Best Contemporary Pop Performance, Chorus) and in 1970. In some years, the Grammy Award for Best Pop Performance by a Duo or Group with Vocal also included performances by a chorus.
Document 11: A cappella: A cappella is gaining popularity among South Asians with the emergence of primarily Hindi-English College groups. The first South Asian a cappella group was Penn Masala, founded in 1996 at the University of Pennsylvania. Co-ed South Asian a cappella groups are also gaining in popularity. The first co-ed south Asian a cappella was Anokha, from the University of Maryland, formed in 2001. Also, Dil se, another co-ed a cappella from UC Berkeley, hosts the "Anahat" competition at the University of California, Berkeley annually. Maize Mirchi, the co-ed a cappella group from the University of Michigan hosts "Sa Re Ga Ma Pella", an annual South Asian a cappella invitational with various groups from the Midwest.
Document 12: Puerto Rico: Puerto Rico (Spanish for ``Rich Port ''), officially the Commonwealth of Puerto Rico (Spanish: Estado Libre Asociado de Puerto Rico, lit.`` Free Associated State of Puerto Rico'') and briefly called Porto Rico, is an unincorporated territory of the United States located in the northeast Caribbean Sea.
Document 13: Puerto Rico: In 1950, the U.S. Congress granted Puerto Ricans the right to organize a constitutional convention via a referendum that gave them the option of voting their preference, ``yes ''or`` no'', on a proposed U.S. law that would organize Puerto Rico as a ``commonwealth ''that would continue United States sovereignty over Puerto Rico and its people. Puerto Rico's electorate expressed its support for this measure in 1951 with a second referendum to ratify the constitution. The Constitution of Puerto Rico was formally adopted on July 3, 1952. The Constitutional Convention specified the name by which the body politic would be known.
Document 14: 51st state: Puerto Rico has been discussed as a potential 51st state of the United States. In a 2012 status referendum a majority of voters, 54%, expressed dissatisfaction with the current political relationship. In a separate question, 61% of voters supported statehood (excluding the 26% of voters who left this question blank). On December 11, 2012, Puerto Rico's legislature resolved to request that the President and the U.S. Congress act on the results, end the current form of territorial status and begin the process of admitting Puerto Rico to the Union as a state.
Document 15: Puerto Rico: On February 4, 1952, the convention approved Resolution 22 which chose in English the word Commonwealth, meaning a ``politically organized community ''or`` state'', which is simultaneously connected by a compact or treaty to another political system. Puerto Rico officially designates itself with the term ``Commonwealth of Puerto Rico ''in its constitution, as a translation into English of the term to`` Estado Libre Asociado'' (ELA).
ground_truth: February 4, 1952
sub_queries: In The Sing-Off, where did the groups not from the United States come from? Answer: Puerto Rico
when did Puerto Rico became a commonwealth of the united states Answer: February 4, 1952