Historical clue formulations

• Odd exception — 2023-01-17
• Surprise for a statistician — 2021-08-04
• Deviation from the norm — 2019-09-04
• Pattern breaker — 2018-05-12
• Quirk — 2015-08-23
• Outlier — 2014-08-14
• It's not normal — 2014-01-25
• Deviation from the norm — 2013-04-03
• Deviation from the standard — 2012-10-01
• Departure, of a sort — 2012-09-15
• Departure from the norm — 2011-10-23
• Blip — 2006-12-01
• It's not the norm — 2003-02-20
• "___ drink Pepsi, but ah'll have a Coke few don't mind" — 1999-12-26
• Odd occurrence — 1998-10-14
• Deviation — 1998-03-25
• Irregularity — 1996-12-18
• Oddball — 1996-04-19