NET EARNINGS PER SHARE

Our basic and diluted earnings per share were:


•	$0.35 during first quarter 2018 and


•	$0.21 during first quarter 2017.

Basic earnings per share is net earnings divided by the weighted average number of our outstanding common shares, including stock equivalent units where there is no circumstance under which those shares would not be issued. Diluted earnings per share is net earnings divided by the sum of the weighted average number of our outstanding common shares and the effect of our outstanding dilutive potential common shares:



	QUARTER ENDED
SHARES IN THOUSANDS	MARCH 2018	MARCH 2017
Weighted average common shares outstanding – basic	756,815	750,665
Dilutive potential common shares:
Stock options	1,682	2,981
Restricted stock units	569	547
Performance share units	396	554
Total effect of outstanding dilutive potential common shares	2,647	4,082
Weighted average common shares outstanding – dilutive	759,462	754,747

We use the treasury stock method to calculate the dilutive effect of our outstanding stock options, restricted stock units and performance share units. Share-based payment awards that are contingently issuable upon the achievement of specified performance or market conditions are included in our diluted earnings per share calculation in the period in which the conditions are satisfied.

Potential Shares Not Included in the Computation of Diluted Earnings per Share

The following shares were not included in the computation of diluted earnings per share because they were either antidilutive or the required performance or market conditions were not met. Some or all of these shares may be dilutive potential common shares in future periods.



	QUARTER ENDED
SHARES IN THOUSANDS	MARCH 2018	MARCH 2017
Stock options	1,301	1,432
Performance share units	744	568