Historical clue formulations

• Prefix with gram — 2013-07-27
• Prefix meaning one-hundredth — 2013-04-01
• Hundredth: Prefix — 2010-12-08
• Prefix with gram — 2006-09-23
• Prefix with grade — 2004-01-10
• Prefix with grade — 2001-12-09
• Meter leader — 2000-05-31
• Metric prefix — 1997-11-22
• Prefix with meter — 1996-04-01