Question: When did an American politician and senior United States Senator from Kentucky create an endowed institution?
Context: Clarence William Nelson II (born September 29, 1942) is an American politician and a member of the Democratic Party who serves as the senior United States Senator from Florida, in office since 2001.  Nelson began his career in the Florida House of Representatives, where he served from 1972 to 1978.  He then served in the United States House of Representatives from 1979 to 1991.  In January 1986, Nelson became the first sitting member of the United States House of Representatives to fly in space.  He flew as a Payload Specialist on the Space Shuttle "Columbia". John Sidney McCain III (born August 29, 1936) is an American politician who currently serves as the senior United States Senator from Arizona, in that office since 1987.  He was the Republican nominee for President of the United States in the 2008 election, which he lost to Barack Obama. Brian Emanuel Schatz (pronounced ; born October 20, 1972) is an American politician who is the senior United States Senator for Hawaii.  Schatz was appointed by Governor Neil Abercrombie to replace Senator Daniel Inouye after his death in 2012. Claire Conner McCaskill ( ; born July 24, 1953) is an American politician and member of the Democratic Party who serves as the senior United States Senator from Missouri.  She is the first female U.S. Senator elected in Missouri in her own right. John Henry Hoeven III (born March 13, 1957) is an American politician and the senior United States Senator from North Dakota, in office since 2011.  A member of the North Dakota Republican Party, he previously served as the 31st Governor of North Dakota from December 2000 to December 2010.  Hoeven was elected to the U.S. Senate in the November 2, 2010 general election.  He replaced junior Senator Byron L. Dorgan, who chose not to seek re-election.  Hoeven became the senior Senator in 2013 after Kent Conrad retired and was replaced by Heidi Heitkamp, who was once Hoeven's opponent for the Governor's office. Addison Mitchell McConnell Jr. (born February 20, 1942) is an American politician and the senior United States Senator from Kentucky.  A member of the Republican Party, he has been the Majority Leader of the Senate since January 3, 2015.  He is the 15th Republican and the second Kentuckian to lead his party in the Senate.  McConnell is the longest-serving U.S. Senator in Kentucky history. John Randolph Thune (born January 7, 1961) is an American politician and senior United States Senator from South Dakota, a member of the Republican Party.  He previously served as a United States Representative for South Dakota 's at-large congressional  .  He became South Dakota's senior senator with the retirement of Tim Johnson in 2015.  He is South Dakota's senior senator, having served as the GOP's Chief Deputy Whip in 2006, chairman of the Republican Policy Committee in June 2009, and Republican Conference Chairman in 2011, the third-ranking position in the Senate.  He has worked in politics and civic organizations since completing his MBA graduate degree.  He is also the current dean of South Dakota's congressional delegation. Susan Margaret Collins (born December 7, 1952) is an American politician who currently serves as the senior United States Senator from Maine.  A member of the Republican Party, Collins has served in the Senate since 1997, and has served as the Chairwoman of the Senate Special Committee on Aging since 2015 and previously chaired the Senate Committee on Homeland Security from 2003 to 2007.  She is considered a moderate Republican Senator.  She also is known for her long consecutive voting streak, which reached 6,000 votes in September 2015.  She is the current dean of Maine's congressional delegation. Patrick Joseph Leahy (born March 31, 1940) is an American politician and the senior United States Senator from Vermont, since 1975.  A member of the Democratic Party, Leahy served as the President pro tempore of the United States Senate from December 17, 2012, to January 6, 2015.  As President pro tempore, he was third in the presidential line of succession.  He is the most senior senator and took office at 34 years old, younger than any other current senator.  Leahy received the title of President pro tempore emeritus upon the commencement of the 114th Congress.  He is the last remaining member of the Senate to have served prior to the 1976 election of President Jimmy Carter. The McConnell Center is an endowed institution created in 1991 by U.S. Senator Mitch McConnell, and the University of Louisville.
Answer: 1991