Earnings Per Share

6 Months Ended

Jun. 30, 2019

Our basic earnings per share calculations are based on the weighted average number of common shares outstanding during the period. Potentially dilutive securities include outstanding stock options, restricted share units, deferred stock units and performance-based restricted share units. The effect of potentially dilutive securities is reflected in diluted earnings per common share by application of the treasury method. Diluted earnings per share gives effect to all potentially dilutive common shares outstanding during the period.



	Three Months Ended				Six Months Ended
	June 30,				June 30,
(in millions, except per share data)	2019		2018		2019		2018
Net income attributable to common shareholders	$	91.0	$	80.7	$	173.4	$	149.4

Average basic shares outstanding	59.9		59.7		59.8		59.7
Effect of dilutive stock options	0.9		1.4		1.0		1.3
Average diluted shares outstanding	60.8		61.1		60.8		61.0

Earnings per basic share	$	1.52	$	1.35	$	2.90	$	2.50
Earnings per diluted share	$	1.50	$	1.32	$	2.85	$	2.45

The computation of diluted earnings per share excludes the effect of the potential exercise of stock options when the average market price of the common stock is lower than the exercise price of the related stock options. For the three-month periods ended June 30, 2019 and 2018, the number of stock options excluded from the computation was 1.3 million and 0.4 million, respectively. For the six-month periods ended June 30, 2019 and 2018, the number of stock options excluded from the computation was 1.2 million and 0.4 million, respectively.