Basic earnings per share is computed using the weighted average number of shares outstanding during the period, while diluted earnings per share is calculated to reflect the potential dilution that would occur related to the issuance of capital stock under stock option grants, performance awards and restricted stock units. The difference between basic and diluted earnings per share relates solely to the effect of capital stock options, performance awards and restricted stock units.

The following table provides the computation of diluted shares outstanding for the three and six months ended December 31, 2022 and 2021:


	Three Months Ended December 31,		Six Months Ended December 31,
(in thousands)	2022	2021	2022	2021
Weighted-average shares outstanding during the period	80,737	83,637	81,141	83,759
Add: Unexercised stock options and unvested restricted stock units	500	737	536	743
Number of shares on which diluted earnings per share is calculated	81,237	84,374	81,677	84,502
Unexercised stock options with an exercise price greater than the average market price and restricted stock units not included in the computation because they were anti-dilutive	1,388	145	1,373	183