21. Earnings Per Share

The computations of basic and diluted net earnings per share are as follows (in thousands, except per share data):


Year Ended December 31,	2018			2017			2016
Basic net earnings per share:
Basic net earnings	$	2,360,767		$	1,318,688		$	796,271
Earnings allocated to participating securities		(9,344	)		(4,549	)		(2,632	)

Net earnings available to common stockholders	$	2,351,423		$	1,314,139		$	793,639

Average shares outstanding		315,858			319,990			319,563

Basic net earnings per share	$	7.44		$	4.11		$	2.48

Diluted net earnings per share:
Diluted net earnings	$	2,360,767		$	1,318,688		$	796,271
Earnings allocated to participating securities		(9,317	)		(4,539	)		(2,631	)

Net earnings available to common stockholders	$	2,351,450		$	1,314,149		$	793,640

Diluted average shares outstanding:
Basic shares outstanding		315,858			319,990			319,563
Dilutive effect of stock options and other		875			783			259

		316,733			320,773			319,822

Diluted net earnings per share	$	7.42		$	4.10		$	2.48

The following stock options were excluded from the computation of diluted net earnings per share because their effect would have been anti-dilutive (shares in thousands):


Year Ended December 31,	2018		2017		2016
Year Ended December 31,	2018		2017		2016
Anti-dilutive stock options:
Weighted-average shares		156		407		942

Weighted-average exercise price	$	65.80	$	59.07	$	47.04