Net Income Per Share (Tables)

6 Months Ended

Jun. 30, 2011

Net income per share

Net income and shares used in basic and diluted net income per share

The following table reconciles net income and shares used in the calculation of basic net income per share to those used for diluted net income per share:

	Three Months Ended				Six Months Ended
	June 30,				June 30,
($ in millions)	2011		2010		2011		2010
Net income, as reported, for basic net income per share	$	20.1	$	21.7	$	39.7	$	41.6
Plus: interest expense on convertible debt, net of tax		1.1		1.1		2.1		2.1
Net income for diluted net income per share	$	21.2	$	22.8	$	41.8	$	43.7

Weighted average common shares outstanding	33.6	33.3	33.5	33.2
Assumed stock options exercised and awards vested, based on the treasury stock method	0.5	0.5	0.5	0.5
Assumed conversion of convertible debt, based on the if-converted method	2.9	2.9	2.9	2.9
Weighted average shares assuming dilution	37.0	36.7	36.9	36.6