Weighted Average Shares

12 Months Ended

Dec. 31, 2015

Weighted-average shares were calculated as follows (in thousands):



	Year Ended December 31,
	2015	2014	2013
Basic weighted-average common shares outstanding	86,296	86,858	86,946
Effect of dilutive stock options	1,695	2,213	1,955
Diluted weighted-average common and common-equivalent shares outstanding	87,991	89,071	88,901

Stock options to purchase 3,035,078, 1,286,403, and 1,385,901 shares of common stock, on a weighted-average basis, were outstanding in 2015, 2014, and 2013, respectively, but were not included in the calculation of dilutive net income per share because they were anti-dilutive.