Historical clue formulations

• Et ___ — 2017-03-15
• Et ___ — 2017-01-22
• Latin word usually shortened to "c." — 2016-03-26
• Et ___ — 2014-05-02
• Peter with the 1986 #1 hit "Glory of Love" — 2012-08-10
• Et ___ — 2010-10-03
• Et ___ — 2009-06-14
• Et ___ — 2009-04-08
• Latin word usually abbreviated with a single letter — 2005-11-18
• It's usually abbreviated "c." — 2004-05-21
• Et ___ — 2000-06-29
• The rest — 1997-06-27
• Singer Peter — 1994-07-23
• The "c" in etc. — 1994-04-26