2007 everyone made it rookie year
2008 DE Henderson went on IR, QB Woodson to the practice squad
2009 was really the fluke year, both the late round CBs they drafted got waived, (largely because UDFA Bruce Johnson outplayed them), Bomar was originally waived and put on the practice squad, but then made the active roster later in the season.
2010 everyone made it
2011 everyone made it
2012 McCants went to the practice squad, Mosley went on IR. Otherwise everyone made it.
So really the rookies are almost guaranteed to make the team, provided they arent either a QB, or a late round OL.