Historical clue formulations

• Volunteers — 2015-07-19
• Is promoted — 2003-06-05
• Accelerates — 2002-11-22
• Increases — 2001-10-07
• Increases, as production — 2001-04-26
• Accelerates — 1998-11-10
• Increases — 1998-04-19
• Accelerates — 1995-05-28