Historical clue formulations

• Midcentury year — 2019-03-16
• Middle of this century — 2012-02-11
• Mid-century year — 2011-01-13
• Year for Super Bowl LXXXIV — 2006-01-14
• Middle of this century — 2005-02-11
• 21st-century year — 2002-06-23
• Future year — 1997-03-15