Columns: Season | Episodes | Timeslot ( ET ) | Season premiere | Season finale | TV season | Rank | Viewers (in millions)
1 | 22 | Tuesday 8:00pm (2005) Wednesday 8:00pm (2006) | September 13, 2005 | May 17, 2006 | 2005–06 | #60 | 8.90 | 2 | 21 | Wednesday 8:00pm | August 30, 2006 | May 16, 2007 | 2006–07 | #50 | 9.40 | 3 | 15 | Tuesday 8:00pm (2007) Monday 8:00pm (2008) | September 25, 2007 | May 19, 2008 | 2007–08 | #51 | 8.90 | 4 | 26 | Wednesday 8:00pm (2008) Thursday 8:00pm (2009) | September 3, 2008 | May 14, 2009 | 2008–09 | #32 | 10.81 | 5 | 22 | Thursday 8:00pm | September 17, 2009 | May 20, 2010 | 2009–10 | #32 | 10.02 | 6 | 23 | Thursday 8:00pm (2010) Thursday 9:00pm (2011) | September 23, 2010 | May 19, 2011 | 2010–11 | #29 | 11.57