Historical clue formulations

• Adjust at Moody's, say — 2015-05-03
• Downgrade, perhaps — 2013-02-24
• Add a star to, say — 2009-04-21
• Grade again — 2007-08-23
• Change from an R, say — 2004-08-15
• Change from AA to AAA, e.g. — 2003-03-27
• Give more stars to, maybe — 2001-12-15
• Change from X to NC-17, e.g. — 1995-07-08