Earnings Per Share

The following table sets forth the computation of basic and diluted net earnings per share (in millions, except per share data):


	Three-month period ended September 30,				Nine-month period ended September 30,
	2018		2017		2018		2017
Net earnings attributable to controlling interests	$	127.6	$	111.0	$	516.2	$	409.8

Weighted average number of common shares outstanding		183.3		180.5		182.4		179.8
Dilutive effect of stock options using the treasury stock method		3.5		2.0		3.3		1.8

Weighted average number of common and common equivalent shares outstanding		186.8		182.5		185.7		181.6

Basic net earnings per share	$	0.70	$	0.61	$	2.83	$	2.28

Diluted net earnings per share	$	0.68	$	0.61	$	2.78	$	2.26

Options to purchase 1.3 million and 1.7 million shares of common stock were outstanding at September 30, 2018 and 2017, respectively, but were not included in the computation of the dilutive effect of stock options for the three-month periods then ended. Options to purchase 0.9 million and 1.2 million shares of common stock were outstanding at September 30, 2018 and 2017, respectively, but were not included in the computation of the dilutive effect of stock options for the nine-month periods then ended. These stock options were excluded from the computation because the options’ exercise prices were greater than the average market price of our common shares during the respective period, and therefore, would be anti-dilutive to earnings per share under the treasury stock method.