Historical clue formulations

• Breaks in concentration — 2023-03-13
• Expires — 2022-03-17
• Unwanted gaps — 2021-10-25
• Small mistakes — 2009-04-12
• Breaks in concentration — 2008-05-28
• Failures — 2006-01-01
• Memory gaps — 2005-10-04
• Failures — 1999-05-23
• Failures — 1998-08-12
• Slips — 1997-12-19
• Falls into disuse — 1997-10-08
• Backslides — 1996-01-14
• Gaps — 1995-11-07