Weighted Average Shares

12 Months Ended

Dec. 31, 2021

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


	Year Ended December 31,
	2021	2020	2019
Basic weighted-average common shares outstanding	176,463	173,489	171,194
Effect of dilutive stock awards	3,453	3,103	4,075
Diluted weighted-average common and common-equivalent shares outstanding	179,916	176,592	175,269

Stock options to purchase 497,504, 4,371,194, and 5,735,608 shares of common stock, on a weighted-average basis, were outstanding in 2021, 2020, and 2019, respectively, but were not included in the calculation of dilutive net income per share because they were anti-dilutive. Restricted stock units totaling 605, 3,826, and 13,092 shares of common stock, on a weighted-average basis, were outstanding in 2021, 2020, and 2019, respectively, but were not included in the calculation of dilutive net income per share because they were anti-dilutive.