7. Earnings Per Share

The computation of basic earnings per share is based on the weighted average number of common shares outstanding during each period. The computation of diluted earnings per share is based on the weighted average number of common shares outstanding during the period plus, when their effect is dilutive, incremental shares consisting of shares subject to stock options, shares issuable upon vesting of restricted stock awards and shares to be issued upon conversion of convertible debt.

We use the "if-converted" method in calculating the diluted earnings per share effect of the assumed conversion of our contingently convertible debt issued in fiscal 2006 because the principal for that issuance can be settled in stock, cash or a combination thereof. Under the "if converted" method, the after-tax effect of interest expense related to the convertible securities is added back to net income, and the convertible debt is assumed to have been converted into common shares at the beginning of the period.

In accordance with ASC 260-10-45, Share-Based Payment Arrangements and Participating Securities and the Two-Class Method, our unvested restricted stock awards are deemed participating securities since these shares are entitled to participate in dividends declared on common shares. During periods of net income, the calculation of earnings per share for common stock excludes income attributable to unvested restricted stock awards from the numerator and excludes the dilutive impact of those shares from the denominator. During periods of net loss, no effect is given to the participating securities because they do not share in the losses of the Company.

The following tables provide a reconciliation of the computations of basic and diluted earnings per share information for each of the years in the three-year period ended May 31, 2015 (shares in millions).

	For the Year Ended May 31,
	2015			2014			2013
Basic EPS:
Income (Loss) from continuing operations	$	(54.5	)	$	67.2		$	48.8
Less income attributable to participating shares		(0.3	)		(1.5	)		(2.0	)

Income (Loss) from continuing operations attributable to common shareholders		(54.8	)		65.7			46.8
Income from discontinued operations attributable to common shareholders		64.7			5.7			6.2

Net income attributable to common shareholders for earnings per share—basic	$	9.9		$	71.4		$	53.0


Diluted EPS:
Income (Loss) from continuing operations	$	(54.5	)	$	67.2		$	48.8
Add after-tax interest on convertible debt		—			—			3.2
Less income attributable to participating shares		(0.3	)		(1.5	)		(1.9	)

Income (Loss) from continuing operations attributable to common shareholders		(54.8	)		65.7			50.1
Income from discontinued operations attributable to common shareholders		64.7			5.7			6.2

Net income attributable to common shareholders for earnings per share—diluted	$	9.9		$	71.4		$	56.3


Weighted average common shares outstanding—basic		39.1			38.6			38.3
Additional shares from assumed conversion of debt		—			—			2.2
Additional shares from assumed exercise of stock options		0.3			0.5			0.1

Weighted average common shares outstanding—diluted		39.4			39.1			40.6


Earnings per share—basic:
Earnings (Loss) from continuing operations	$	(1.40	)	$	1.70		$	1.23
Earnings from discontinued operations		1.66			0.15			0.15

Earnings per share—basic	$	0.26		$	1.85		$	1.38


Earnings per share—diluted:
Earnings (Loss) from continuing operations	$	(1.40	)	$	1.68		$	1.23
Earnings from discontinued operations		1.64			0.15			0.15

Earnings per share—diluted	$	0.24		$	1.83		$	1.38

At May 31, 2015, 2014 and 2013, respectively, options to purchase 168,200 shares, 180,000 shares, and 872,200 shares of common stock were outstanding, but were not included in the computation of diluted earnings per share, because the exercise price of these options was greater than the average market price of the common shares for the period then ended.