Question: When did the football coach, who led the 2004 Oklahoma Sooners team,  announce his retirement?

full_context: Document 1: 2005 Oklahoma Sooners football team: The 2005 Oklahoma Sooners football team represented the University of Oklahoma in the 2005 NCAA Division I-A football season, the 111th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his seventh season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 Conference.
Document 2: 2010 Oklahoma Sooners football team: The 2010 Oklahoma Sooners football team represented the University of Oklahoma in the 2010 NCAA Division I FBS football season, the 116th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his 12th season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 Conference.
Document 3: 2009 Oklahoma Sooners football team: The 2009 Oklahoma Sooners football team represented the University of Oklahoma in the 2009 NCAA Division I FBS football season, the 115th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his 11th season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 Conference.
Document 4: Bob Stoops: Robert Anthony Stoops (born September 9, 1960) is a former American college football coach. He is the former head football coach at the University of Oklahoma, a position he held from 1999 until he announced his retirement June 7, 2017. During the 2000 season, Stoops led the Sooners to an Orange Bowl victory and a national championship.
Document 5: 2016 Oklahoma Sooners football team: The 2016 Oklahoma Sooners football team represented the University of Oklahoma in the 2016 NCAA Division I FBS football season, the 122nd season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his 18th season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They are a charter member of the Big 12 Conference.
Document 6: 2007 Oklahoma Sooners football team: The 2007 Oklahoma Sooners football team represented the University of Oklahoma in the 2007 NCAA Division I FBS football season, the 113th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his ninth season as head coach. They played their homes games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 Conference.
Document 7: 2012 Oklahoma Sooners football team: The 2012 Oklahoma Sooners football team represented the University of Oklahoma in the 2012 NCAA Division I FBS football season, the 118th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his 14th season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 Conference.
Document 8: 2013 Oklahoma Sooners football team: The 2013 Oklahoma Sooners football team represented the University of Oklahoma in the 2013 NCAA Division I FBS football season, the 119th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his 15th season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 Conference.
Document 9: 2004 Oklahoma Sooners football team: The 2004 Oklahoma Sooners football team represented the University of Oklahoma during the 2004 NCAA Division I-A football season, the 110th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his sixth season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 conference.
Document 10: 2000 Oklahoma Sooners football team: The 2000 Oklahoma Sooners football team represented the University of Oklahoma in the 2000 NCAA Division I-A football season, the 106th season of Sooner football. The team was led by Bob Stoops in his second season as head coach. They played their home games at Oklahoma Memorial Stadium in Norman. During this season, they competed in the Big 12 Conference.
Document 11: 2015 Oklahoma Sooners football team: The 2015 Oklahoma Sooners football team represented the University of Oklahoma in the 2015 NCAA Division I FBS football season, the 121st season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his 17th season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 Conference.
Document 12: 2006 Oklahoma Sooners football team: The 2006 Oklahoma Sooners football team represented the University of Oklahoma in the 2006 NCAA Division I FBS football season, the 112th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his eighth season as head coach. They played their homes games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 Conference.
Document 13: 2014 Oklahoma Sooners football team: The 2014 Oklahoma Sooners football team represented the University of Oklahoma in the 2014 NCAA Division I FBS football season, the 120th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner, Bob Stoops, in his 16th season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a member of the Big 12 Conference.
Document 14: 2003 Oklahoma Sooners football team: The 2003 Oklahoma Sooners football team represented the University of Oklahoma in the 2003 NCAA Division I-A football season, the 109th season of Sooner football. The team was led by two-time Walter Camp Coach of the Year Award winner (winning his second one that season), Bob Stoops, in his fifth season as head coach. They played their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma. They were a charter member of the Big 12 Conference.
Document 15: Mike Stoops: Michael Joseph Stoops (born December 13, 1961) is an American football coach and former player. He is currently the defensive coordinator at the University of Oklahoma. Stoops served as the head football coach at the University of Arizona from 2003 until his firing during the 2011 season. He previously served as an assistant coach at the University of Iowa, Kansas State University, and Oklahoma. He is the younger brother of Bob Stoops, the former head coach of the Oklahoma Sooners football program, and the older brother of Mark Stoops, head coach at the University of Kentucky.
ground_truth: June 7, 2017