. per share data : basic earnings per share calculations were computed by dividing net earnings by the corresponding weighted-average number of common shares outstanding for the period . the dilutive effect of the potential exercise of outstanding options to purchase common shares is calculated using the treasury stock method . snap-on had dilutive shares as of year-end 2007 , 2006 and 2005 , of 731442 shares , 911697 shares and 584222 shares , respectively