( a ) additional shares were issued in 2006 and 2007 because the performance targets were exceeded for the 36-month performance periods related to the 2003 and 2004 grants . during 2007 , 2006 and 2005 the weighted average grant date fair value of restricted stock awards was $ 54.97 , $ 40.45 and $ 27.21 . the vesting date fair value of stock-based performance awards which vested during 2007 , 2006 and 2005 was $ 38 million , $ 21 million and $ 5 million