Columns: Season | Episodes | Timeslot ( EST ) | Season premiere | Season finale | TV season | Rank | Viewers (in millions)
1 | 22 | Wednesday 9:00pm | September 22, 2005 | May 10, 2006 | 2005–06 | No. 28 | 12.63 | 2 | 23 | Wednesday 9:00pm | September 20, 2006 | May 16, 2007 | 2006–07 | No. 24 | 14.05 | 3 | 20 | Wednesday 9:00pm | September 26, 2007 | May 21, 2008 | 2007–08 | No. 24 | 12.78 | 4 | 26 | Wednesday 9:00pm | September 24, 2008 | May 20, 2009 | 2008–09 | No. 11 | 14.95 | 5 | 23 | Wednesday 9:00pm | September 23, 2009 | May 26, 2010 | 2009–10 | No. 16 | 13.70 | 6 | 24 | Wednesday 9:00pm | September 22, 2010 | May 18, 2011 | 2010–11 | No. 10 | 14.11 | 7 | 24 | Wednesday 9:00pm | September 21, 2011 | May 16, 2012 | 2011–12 | No. 15 | 13.20