Question: When did the country of which Andris Ameriks is a citizen become part of the USSR?

full_context: Document 1: Lithuanian Soviet Socialist Republic: The Lithuanian Soviet Socialist Republic (Lithuanian SSR; Lithuanian: Lietuvos Tarybų Socialistinė Respublika; Russian: Литовская Советская Социалистическая Республика, Litovskaya Sovetskaya Sotsialisticheskaya Respublika), also known as Soviet Lithuania or Lithuania was a republic of the Soviet Union. It existed from 1940 to 1990.
Document 2: Juris Bārzdiņš: Juris Bārzdiņš (born 21 July 1966) is a Latvian politician, member of the Union of Greens and Farmers party and the incumbent Minister of Health of Latvia since 3 November 2010.
Document 3: Estonia: On 6 August 1940, Estonia was annexed by the Soviet Union as the Estonian SSR. The provisions in the Estonian constitution requiring a popular referendum to decide on joining a supra-national body were ignored. Instead the vote to join the Soviet Union was taken by those elected in the elections held the previous month. Additionally those who had failed to do their "political duty" of voting Estonia into the USSR, specifically those who had failed to have their passports stamped for voting, were condemned to death by Soviet tribunals. The repressions followed with the mass deportations carried out by the Soviets in Estonia on 14 June 1941. Many of the country's political and intellectual leaders were killed or deported to remote areas of the USSR by the Soviet authorities in 1940–1941. Repressive actions were also taken against thousands of ordinary people.
Document 4: Estonia: Estonia is a parliamentary representative democratic republic in which the Prime Minister of Estonia is the head of government and which includes a multi-party system. The political culture is stable in Estonia, where power is held between two and three parties that have been in politics for a long time. This situation is similar to other countries in Northern Europe. The former Prime Minister of Estonia, Andrus Ansip, is also Europe's longest-serving Prime Minister (from 2005 until 2014). The current Estonian Prime Minister is Taavi Rõivas, who is the former Minister of Social Affairs and the head of the Estonian Reform Party.
Document 5: Molotov–Ribbentrop Pact: In mid-June 1940, when international attention was focused on the German invasion of France, Soviet NKVD troops raided border posts in Lithuania, Estonia and Latvia. State administrations were liquidated and replaced by Soviet cadres, in which 34,250 Latvians, 75,000 Lithuanians and almost 60,000 Estonians were deported or killed. Elections were held with single pro-Soviet candidates listed for many positions, with resulting peoples assemblies immediately requesting admission into the USSR, which was granted by the Soviet Union. The USSR annexed the whole of Lithuania, including the Scheschupe area, which was to be given to Germany.
Document 6: Sarmīte Ēlerte: Sarmīte Ēlerte (born 8 April 1957, Riga, Latvian SSR) is a Latvian politician, member of the Unity party and former Minister of Culture of Latvia from 3 November 2010 until 25 October 2011.
Document 7: Post-Soviet states: The post-Soviet states, also collectively known as the former Soviet Union (FSU) or former Soviet Republics, are the 15 independent states that emerged from the Union of Soviet Socialist Republics in its dissolution in December 1991, with Russia internationally recognised as the successor state to the Soviet Union. On March 11, 1990, Lithuania was the first to declare its independence, with Estonia and Latvia following suit in August 1991. All three Baltic states claimed continuity from the original states that existed prior to their annexation by the Soviet Union in 1944 and were admitted to the United Nations on 17 September 1991. The remaining 12 republics all subsequently seceded. 12 of the 15 states, excluding the Baltic states, initially formed the CIS and most joined CSTO, while the Baltic states focused on European Union and NATO membership.
Document 8: Andris Ameriks: Andris Ameriks (born March 5, 1961 in Jūrmala, Soviet Union) is a Latvian politician, economist and former deputy mayor of Riga.
Document 9: Anatols Dinbergs: Anatols Dinbergs (born Riga, March 3, 1911, died Washington, D.C., November 9, 1993) was one of the preeminent career diplomats of Latvia. He entered service in Latvia's Foreign Ministry in 1932. Dinbergs remained abroad when the Soviet Union occupied Latvia, serving in the Latvian Legation in Washington, D.C., after World War II ended. Dinbergs assumed the highest diplomatic post, that of "chargé d'affaires", in 1970 and represented Latvia's sovereign interests in exile until Latvia reestablished its independence in 1991. As head of the Latvian diplomatic service abroad, Dinbergs was appointed Latvia's first ambassador to the United Nations and subsequently Latvia's first ambassador to the United States. After retirement, he served as Counselor to the Latvian Embassy in Washington, D.C., until his death in 1993.
Document 10: Ivars Godmanis: Ivars Godmanis (born 27 November 1951) is a Latvian politician who was Prime Minister of Latvia from 1990 to 1993 and again from 2007 to 2009. He was the first Prime Minister of Latvia after the country restored its independence from the Soviet Union.
Document 11: Aigars Kalvītis: On 2 December 2004, he became the Prime Minister of Latvia. He was the prime minister of Latvia until his resignation on 5 December 2007.
Document 12: History of Latvia: The First Latvian National Awakening began in the 1850s and continued to bear fruit after World War I when, after two years of struggle in the Latvian War of Independence, Latvia finally won sovereign independence, as recognised by Soviet Russia in 1920 and by the international community in 1921. The Constitution of Latvia was adopted in 1922. Political instability and effects of the Great Depression led to the May 15, 1934 coup d'état by Prime Minister Kārlis Ulmanis. Latvia's independence was interrupted in June -- July 1940, when the country was occupied and incorporated into the Soviet Union. In 1941 it was invaded and occupied by Nazi Germany, then reconquered by the Soviets in 1944 -- 45.
Document 13: Latvian Soviet Socialist Republic: Following the Welles Declaration of July 23, 1940, the annexation of Latvia into the Soviet Union (USSR) on 5 August 1940 was not recognized as legitimate by the United States, the European Community, and recognition of it as the nominal fifteenth constituent republic of the USSR was withheld for five decades. Its territory was subsequently conquered by Nazi Germany in June -- July 1941, before being retaken by the Soviets in 1944 -- 1945. Nevertheless, Latvia continued to exist as a de jure independent country with a number of countries continued to recognize Latvian diplomats and consuls who still functioned in the name of their former governments.
Document 14: Dissolution of the Soviet Union: On June 14, 1987, about 5,000 people gathered again at Freedom Monument in Riga, and laid flowers to commemorate the anniversary of Stalin's mass deportation of Latvians in 1941. This was the first large demonstration in the Baltic republics to commemorate the anniversary of an event contrary to official Soviet history. The authorities did not crack down on demonstrators, which encouraged more and larger demonstrations throughout the Baltic States. The next major anniversary after the August 23 Molotov Pact demonstration was on November 18, the date of Latvia’s independence in 1918. On November 18, 1987, hundreds of police and civilian militiamen cordoned off the central square to prevent any demonstration at Freedom Monument, but thousands lined the streets of Riga in silent protest regardless.
Document 15: Estonia: In 1989, during the "Singing Revolution", in a landmark demonstration for more independence, more than two million people formed a human chain stretching through Lithuania, Latvia and Estonia, called the Baltic Way. All three nations had similar experiences of occupation and similar aspirations for regaining independence. The Estonian Sovereignty Declaration was issued on 16 November 1988. On 20 August 1991, Estonia declared formal independence during the Soviet military coup attempt in Moscow, reconstituting the pre-1940 state. The Soviet Union recognised the independence of Estonia on 6 September 1991. The first country to diplomatically recognise Estonia's reclaimed independence was Iceland. The last units of the Russian army left on 31 August 1994.
ground_truth: 5 August 1940
sub_queries: Of which country is Andris Ameriks a citizen? Answer: Latvia
when did Latvia become part of the soviet union Answer: 5 August 1940