18.EARNINGS PER SHARE

The following table sets forth the computation of basic and diluted earnings per share:



	September 30,
	2018		2017		2016
(In millions, except per share data)
Numerator
Net Income Attributable to Versum	$	197.5	$	193.3	$	209.3
Denominator
Weighted average number of common shares - Basic	108.9		108.7		108.7
Effect of dilutive securities
Employee stock option and other award plans	0.9		0.7		—
Weighted average number of common shares - Diluted	109.8		109.4		108.7

Earnings Per Common Share Attributable to Versum
Net Income Attributable to Versum - Basic	$	1.81	$	1.78	$	1.93
Net Income Attributable to Versum - Diluted	1.80		1.77		1.93

For periods prior to the Separation, the computation of basic and diluted earnings per common share is calculated assuming the number of shares of Versum common stock outstanding on October 1, 2016 had been outstanding at the beginning of each period presented. For the periods prior to the Separation, it is assumed that there are no dilutive equity instruments as there were no equity awards in Versum outstanding prior to the Separation. See Note 1, “Basis of Presentation” for further discussion of the Separation.

For the year ended September 30, 2018, outstanding share-based awards of 0.2 million shares were anti-dilutive and therefore excluded from the computation of diluted earnings per share. For the year ended September 30, 2017, no outstanding share-based awards were anti-dilutive.