Earnings Per Share

12 Months Ended

Dec. 31, 2012

Earnings Per Share

Earnings Per Share

15. Earnings Per Share

The following table presents earnings attributable to common shareholders per weighted-average common share outstanding for the years ended December 31, 2012, 2011 and 2010:

	2012			2011		2010
Basic earnings per share:
Income from continuing operations attributable to common shareholders	$	3.54		$	3.01	$	3.05
Income (loss) from discontinued operations	(0.06		)	0.10		0.23
Earnings per share — basic	$	3.48		$	3.11	$	3.28
Diluted earnings per share:
Income from continuing operations attributable to common shareholders	$	3.50		$	2.99	$	3.03
Income (loss) from discontinued operations	(0.05		)	0.10		0.24
Earnings per share — diluted	$	3.45		$	3.09	$	3.27

Dilutive stock options and performance shares (which are contingently issuable) increased average common shares outstanding by approximately 1,017,000 shares in 2012, 811,000 shares in 2011 and 565,000 shares in 2010.  Total average common shares outstanding for the purposes of calculating diluted earnings per share were 110,527,311 shares in 2012, 109,864,243 shares in 2011 and 107,137,785 shares in 2010.

For the years ended 2012 and 2011, there were no common stock options that were excluded from the computation of diluted earnings per share as a result of the options’ exercise prices being greater than the average market price of the common shares.  Options to purchase shares of common stock that were not included in the computation of diluted earnings per share were 192,542 during 2010.