Historical clue formulations

• Never — 2012-11-12
• Never — 2007-04-03
• Never — 2002-10-13
• Never ever — 2001-01-07
• When hell freezes over — 1999-01-23
• Never — 1996-02-24
• Never ever — 1994-01-29
• Never — 1993-12-10