Question: In what year did the Uganda President's regime kill the first prime minister of Uganda?

full_context: Document 1: The Collected Broadcasts of Idi Amin: The Collected Broadcasts of Idi Amin is a British comedy album parodying Ugandan dictator Idi Amin, released in 1975 on Transatlantic Records. It was performed by John Bird and written by Alan Coren, based on columns he wrote for "Punch" magazine.
Document 2: Henry Kyemba: Henry Kyemba (born December 1939) is a Ugandan political figure who held several high positions and finally became Minister of Health during Uganda's rule by Idi Amin. He is also the author of "State of Blood", a 1977 book he wrote after his flight from Uganda that describes Amin's tyrannical rule.
Document 3: Geoffrey Oryema: Geoffrey Oryema (born 16 April 1953) is an internationally renowned Ugandan musician. In 1977, at the age of 24 and at the height of Idi Amin's power, Oryema was smuggled across the Ugandan border in the trunk of a car, after the murder of his father, Erinayo Wilson Oryema, who was a cabinet minister in the government of Amin, beginning a life in exile.
Document 4: Idi Amin: Idi Amin Dada ( ;  1923 2816 August 2003) was a Ugandan political leader and military officer who was the President of Uganda from 1971 to 1979.
Document 5: Benedicto Kiwanuka: Benedicto Kagimu Mugumba Kiwanuka (8 May 1922 – 22 September 1972) was the first prime minister of Uganda, a leader of the Democratic Party, and one of the persons that led the country in the transition between colonial British rule and independence. He was murdered by Idi Amin's regime in 1972.
Document 6: Erinayo Wilson Oryema: Erinayo Wilson Oryema CPM (1 January 1917 – 16 February 1977) was Uganda's first African Inspector General of Police (1964-1971), Minister of Land, Mineral, and Water Resources (1971-1974) and Minister of Land, Housing and Physical Planning (1974-1977). In February 1977, Oryema, together with Archbishop Janani Luwum and Interior Minister Charles Oboth Ofumbi, is generally accepted as having been murdered by the security forces of the government of President Idi Amin.
Document 7: George Cadle Price: George Cadle Price, PC, OCC (15 January 191919 September 2011), was a Belizean statesman who served twice as the head of government of Belize from 1961–84 and 1989–93. He served as First Minister and Premier under British rule until independence in 1981 and was the nation's first prime minister after independence that year. He is considered to have been one of the principal architects of Belizean independence. Today he is referred to by many as the "Father of the Nation." Price effectively dominated Belizean politics from the early 1960s until his 1996 retirement from party leadership, serving as the nation's head of government under various titles for most of that period.
Document 8: Milton Obote: Apollo Milton Obote (28 December 1925 – 10 October 2005) was a Ugandan political leader who led Uganda to independence in 1962 from British colonial administration. Following the nation's independence, he served as Prime Minister of Uganda from 1962 to 1966 and President of Uganda from 1966 to 1971, then again from 1980 to 1985. He was overthrown by Idi Amin in 1971, but regained power after Amin's 1979 overthrow. His second period of rule was marred by repression and the deaths of many civilians as a result of a civil war known as the Ugandan Bush War.
Document 9: General Idi Amin Dada: A Self Portrait: General Idi Amin Dada: A Self Portrait (French: "Général Idi Amin Dada: Autoportrait" ) is a 1974 documentary film by French director Barbet Schroeder with English dialogue. It was made with the support and participation of its subject, the Ugandan dictator Idi Amin. The film depicts Amin at the height of his power as the ruler of Uganda.
Document 10: Prime Minister of Kenya: The Prime Minister of Kenya was a post in the Kenyan government. The first Prime Minister of Kenya was Jomo Kenyatta who became Prime Minister in 1963. In 1964, Kenya became a Republic; the post of Prime Minister was abolished and Jomo Kenyatta assumed the position of President. Following a power-sharing agreement in February 2008, the post of Prime Minister was recreated that April. The position was again abolished by the 2010 Constitution after the 2013 elections.
Document 11: Barthélemy Boganda: Barthélemy Boganda (4 April 1910 – 29 March 1959) was the leading nationalist politician of what is now the Central African Republic. Boganda was active prior to his country's independence, during the period when the area, part of French Equatorial Africa, was administered by France under the name of Oubangui-Chari. He served as the first Prime Minister of the Central African Republic autonomous territory.
Document 12: Omar al-Bashir: Omar Hassan Ahmad al-Bashir (Arabic: عمر حسن أحمد البشير‎ ‎ ; pronunciation: ] ; born 1 January 1944) is a Sudanese politician, the seventh president of Sudan and head of the National Congress Party. He came to power in 1989 when, as a brigadier in the Sudanese Army, he led a group of officers in a military coup that ousted the democratically elected government of prime minister Sadiq al-Mahdi after it began negotiations with rebels in the south. Since then, he has been elected three times as President in elections that have been under scrutiny for corruption. In March 2009, al-Bashir became the first sitting president to be indicted by the International Criminal Court (ICC), for allegedly directing a campaign of mass killing, rape, and pillage against civilians in Darfur.
Document 13: Ugandan Bush War: The Ugandan Bush War, also known as the Luwero War, the Ugandan civil war or the Resistance War, refers to the guerrilla war waged between 1981 and 1986 in Uganda by the National Resistance Army (NRA) under the leadership of Yoweri Museveni against the government of Milton Obote, and later that of Tito Okello.
Document 14: Muammar Gaddafi: Muammar Mohammed Abu Minyar Gaddafi ( ;    ;  1942 20 October 2011), commonly known as Colonel Gaddafi, was a Libyan revolutionary, politician, and political theorist. He governed Libya as Revolutionary Chairman of the Libyan Arab Republic from 1969 to 1977, then as the "Brotherly Leader" of the Great Socialist People's Libyan Arab Jamahiriya from 1977 to 2011. He was initially ideologically committed to Arab nationalism and Arab socialism, but later came to rule under his own Third International Theory.
Document 15: Edward Lowassa: Edward Ngoyai Lowassa (born August 26, 1953) is a Tanzanian politician who was Prime Minister of Tanzania from 2005 to 2008, serving under President Jakaya Kikwete. Lowassa has gone into record as the first Prime Minister to have been forced to resign by a fraud scandal in the history of Tanzania. Following his resignation President Kikwete was obliged to dissolve his cabinet as required by the Constitution and with minimum delay, constituted a new one under a new Prime Minister, Mizengo Pinda.
ground_truth: 1972