. the fair value of performance awards is calculated using the market value of a share of snap-on 2019s common stock on the date of grant . the weighted-average grant date fair value of performance awards granted during 2012 , 2011 and 2010 was $ 60.00 , $ 55.97 and $ 41.01 , respectively . vested performance share units approximated 213000 shares as of 2012 year end and 54208 shares as of 2011 year end ; there were no vested performance share units as of 2010 year end