Historical clue formulations

• Prefix with -stat — 2011-07-20
• Stat starter — 2010-10-07
• Current: Prefix — 2010-02-28
• -stat starter — 2010-01-10
• Prefix with -stat — 2007-02-10
• Stat starter — 2003-06-15
• Stat start — 2001-12-13
• Stat start — 2000-03-15
• Prefix with -stat — 1999-12-13
• Current: Prefix — 1998-02-22
• Stat starter — 1993-12-15