The following table provides weighted average share information used in the calculation of the Company’s basic and diluted earnings per share:

DECEMBER 31	2020			2019			2018
(in millions, except per share data)
Basic shares used in the calculation of earnings per share		37.7			40.0			42.4
Dilutive effect of securities:
Employee stock options		0.2			0.3			0.3
Non-vested stock grants		0.2			0.3			0.3
Diluted shares used in the calculation of earnings per share		38.1			40.6			43.0
Per share effect of dilutive securities on income from continuing operations	$	(0.11	)	$	(0.16	)	$	(0.07	)
Per share effect of dilutive securities on net income	$	(0.10	)	$	(0.16	)	$	(0.12	)

Diluted earnings per share during 2020, 2019 and 2018 excludes 0.4 million, 0.2 million and 0.3 million, respectively, of common shares issuable under the Company’s stock compensation plans, because their effect would be antidilutive.

The Board of Directors has authorized a stock repurchase program which provides for aggregate repurchases of the Company’s common stock of up to $900 million, and under which the Company had approximately $124 million available at December 31, 2020. Under the repurchase authorization, the Company may repurchase, from time to time, common stock in amounts, at prices and at such times as the Company deems appropriate, subject to market conditions and other considerations. Repurchases may be executed using open market purchases, privately negotiated transactions, accelerated repurchase programs or other transactions. The Company is not required to purchase any specific number of shares or to make purchases by any certain date under this program. During 2020, 2019 and 2018, the Company had executed several accelerated share repurchase (“ASR”) agreements, through which it repurchased a total of 5.2 million shares. Pursuant to the terms of ASR agreements executed on December 30, 2018 and on June 28, 2019, the Company repurchased approximately 3.2 million shares of its common stock for $400.0 million. On December 9, 2019 (the "December 2019 ASR"), the Company repurchased approximately 0.9 million shares of its common stock for $150.0 million pursuant to an additional ASR, which represented approximately 80% of the total number of shares expected to be repurchased under this agreement. On February 26, 2020, the Company received approximately 0.2 million of its common stock shares as a final settlement of shares repurchased under the December 2019 ASR. On October 29, 2020, pursuant to the terms of another ASR agreement (the "October 2020 ASR") the Company paid $100.0 million and received an initial delivery of approximately 0.8 million shares of its common stock, which was approximately 80% of the total number of shares expected to be repurchased under the October 2020 ASR. On January 29, 2021, the Company received approximately 45,000 shares of its common stock shares as final settlement of shares repurchased under the October 2020 ASR.