Historical clue formulations

• The 1900s, e.g.: Abbr. — 2025-10-24
• One of 10 in a millennium: Abbr. — 2025-04-24
• Long life: Abbr. — 2019-08-01
• The 2000s, e.g.: Abbr. — 2019-04-19
• 1900s, e.g.: Abbr. — 2016-01-24
• 100 yrs. — 2014-10-20
• 2000s, e.g.: Abbr. — 2014-08-13
• 800s, e.g.: Abbr. — 2014-07-05
• 100 years: Abbr. — 2012-08-21
• 2000s, e.g.: Abbr. — 2012-04-13
• 1900-99, e.g.: Abbr. — 2009-12-09
• Long time: Abbr. — 2009-10-30
• 100 years: Abbr. — 2009-07-07
• About 877,000 hrs. — 2009-06-21
• What few people live for: Abbr. — 2009-03-06
• 100 yrs. — 2006-09-27
• The 21st, e.g.: Abbr. — 2004-05-21
• Long time: Abbr. — 2003-12-27
• Long time: Abbr. — 2002-12-24
• Fivescore yrs. — 2002-08-20
• 100 yrs. — 2002-05-26
• The 900's, e.g.: Abbr. — 2001-02-15
• 100 yrs. — 2000-12-13
• 100 yrs. — 1999-09-02
• The 1000's, e.g.: Abbr. — 1999-07-30
• The 1900's, e.g.: Abbr. — 1998-09-04
• The 21st, e.g.: Abbr. — 1997-11-30
• Midmost: Abbr. — 1997-07-19
• Mid. — 1997-06-22
• 100 yrs. — 1996-09-24
• 100 yrs. — 1996-01-22
• 100 yrs. — 1995-05-02
• 100 yrs. — 1995-03-05
• 1800's, e.g.: Abbr. — 1994-09-24