Question: When did the country of the groups not from the United States in The Sing-Off gain their independence from Spain?

full_context: Document 1: 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 2: 51st state: Puerto Rico has been under U.S. sovereignty for over a century when it was ceded to the U.S. by Spain following the end of the Spanish–American War, and Puerto Ricans have been U.S. citizens since 1917. The island's ultimate status has not been determined as of 2012[update], its residents do not have voting representation in their federal government. Puerto Rico has limited representation in the U.S. Congress in the form of a Resident Commissioner, a delegate with limited no voting rights. Like the states, Puerto Rico has self-rule, a republican form of government organized pursuant to a constitution adopted by its people, and a bill of rights.
Document 3: History of Puerto Rico: On August 10, 1815, the Royal Decree of Grace was issued, allowing foreigners to enter Puerto Rico (including French refugees from Hispaniola), and opening the port to trade with nations other than Spain. This was the beginning of agriculture-based economic growth, with sugar, tobacco, and coffee being the main products. The Decree also gave free land to anyone who swore their loyalty to the Spanish Crown and their allegiance to the Roman Catholic Church. Thousands of families from all regions of Spain (particularly Asturias, Catalonia, Majorca and Galicia), Germany, Corsica, Ireland, France, Portugal, the Canary Islands and other locations, escaping from harsh economic times in Europe and lured by the offer of free land, soon immigrated to Puerto Rico. However, these small gains in autonomy and rights were short lived. After the fall of Napoleon, absolute power returned to Spain, which revoked the Cádiz Constitution and reinstated Puerto Rico to its former condition as a colony, subject to the unrestricted power of the Spanish monarch.
Document 4: Puerto Rico: Originally populated by the indigenous Taíno people, the island was claimed in 1493 by Christopher Columbus for Spain during his second voyage. Later it endured invasion attempts from the French, Dutch, and British. Four centuries of Spanish colonial government influenced the island's cultural landscapes with waves of African slaves, Canarian, and Andalusian settlers. In the Spanish Empire, Puerto Rico played a secondary, but strategic role when compared to wealthier colonies like Peru and the mainland parts of New Spain. Spain's distant administrative control continued up to the end of the 19th century, helping to produce a distinctive creole Hispanic culture and language that combined elements from the Native Americans, Africans, and Iberians. In 1898, following the Spanish -- American War, the United States acquired Puerto Rico under the terms of the Treaty of Paris. The treaty took effect on April 11, 1899.
Document 5: A cappella: The Swingle Singers used nonsense words to sound like instruments, but have been known to produce non-verbal versions of musical instruments. Like the other groups, examples of their music can be found on YouTube. Beatboxing, more accurately known as vocal percussion, is a technique used in a cappella music popularized by the hip-hop community, where rap is often performed a cappella also. The advent of vocal percussion added new dimensions to the a cappella genre and has become very prevalent in modern arrangements. Petra Haden used a four-track recorder to produce an a cappella version of The Who Sell Out including the instruments and fake advertisements on her album Petra Haden Sings: The Who Sell Out in 2005. Haden has also released a cappella versions of Journey's "Don't Stop Believin'", The Beach Boys' "God Only Knows" and Michael Jackson's "Thriller". In 2009, Toyota commissioned Haden to perform three songs for television commercials for the third-generation Toyota Prius, including an a cappella version of The Bellamy Brothers' 1970s song "Let Your Love Flow".[citation needed]
Document 6: 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 7: Puerto Rico: Originally populated by the indigenous Taíno people, the island was claimed in 1493 by Christopher Columbus for the Crown of Castile during his second voyage. Later it endured invasion attempts from the French, Dutch, and British. Four centuries of Spanish colonial government transformed the island's ethnic, cultural and physical landscapes primarily with waves of African slaves, Canarian, and Andalusian settlers. In the Spanish imperial imagination, Puerto Rico played a secondary, but strategic role when compared to wealthier colonies like Peru and the mainland parts of New Spain. Spain's distant administrative control continued up to the end of the 19th century, helping to produce a distinctive creole Hispanic culture and language that combined elements from the Native Americans, Africans, and Iberians. In 1898, following the Spanish -- American War, the United States acquired Puerto Rico under the terms of the Treaty of Paris.
Document 8: 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 9: 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 10: 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 11: History of Puerto Rico: Located in the northeastern Caribbean, Puerto Rico formed a key part of the Spanish Empire from the early years of the exploration, conquest and colonization of the New World. The island was a major military post during many wars between Spain and other European powers for control of the region in the 16th, 17th and 18th centuries. The smallest of the Greater Antilles, Puerto Rico was a stepping - stone in the passage from Europe to Cuba, Mexico, Central America, and the northern territories of South America. Throughout most of the 19th century until the conclusion of the Spanish -- American War, Puerto Rico and Cuba were the last two Spanish colonies in the New World; they served as Spain's final outposts in a strategy to regain control of the American continents. Realizing that it was in danger of losing its two remaining Caribbean territories, the Spanish Crown revived the Royal Decree of Graces of 1815. The decree was printed in Spanish, English and French in order to attract Europeans, with the hope that the independence movements would lose their popularity and strength with the arrival of new settlers. Free land was offered to those who wanted to populate the islands on the condition that they swear their loyalty to the Spanish Crown and allegiance to the Roman Catholic Church.
Document 12: Independence movement in Puerto Rico: After four hundred years of colonial rule by the Spanish Empire, Puerto Rico finally received its sovereignty in 1897 through a Carta de Autonomía (Charter of Autonomy). It was signed by Spanish Prime Minister Práxedes Mateo Sagasta and ratified by the Spanish Cortes.
Document 13: 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 14: Puerto Rico: Originally populated by the indigenous Taíno people, the island was claimed in 1493 by Christopher Columbus for Spain during his second voyage. Later it endured invasion attempts from the French, Dutch, and British. Four centuries of Spanish colonial government influenced the island's cultural landscapes with waves of African slaves, Canarian, and Andalusian settlers. In the Spanish Empire, Puerto Rico played a secondary, but strategic role when compared to wealthier colonies like Peru and the mainland parts of New Spain. Spain's distant administrative control continued up to the end of the 19th century, helping to produce a distinctive creole Hispanic culture and language that combined elements from the Native Americans, Africans, and Iberians. In 1898, following the Spanish -- American War, the United States acquired Puerto Rico under the terms of the Treaty of Paris.
Document 15: 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.
ground_truth: 1897
sub_queries: In The Sing-Off, where did the groups not from the United States come from? Answer: Puerto Rico
when did Puerto Rico gain their independence from spain Answer: 1897