Basic earnings per share is net earnings divided by the weighted average number of our outstanding common shares, including stock equivalent units where there is no circumstance under which those shares would not be issued. Diluted earnings per share is net earnings divided by the sum of the weighted average number of our outstanding common shares and the effect of our outstanding dilutive potential common shares.

	QUARTER ENDED				YEAR-TO-DATE ENDED
SHARES IN THOUSANDS	JUNE 2022		JUNE 2021		JUNE 2022		JUNE 2021
Weighted average common shares outstanding – basic		744,542		750,127		746,017		749,429
Dilutive potential common shares:
Stock options		308		443		346		330
Restricted stock units		410		659		415		699
Performance share units		322		279		416		315
Total effect of outstanding dilutive potential common shares		1,040		1,381		1,177		1,344
Weighted average common shares outstanding – dilutive		745,582		751,508		747,194		750,773

We use the treasury stock method to calculate the dilutive effect of our outstanding stock options, restricted stock units and performance share units.

The following shares were not included in the computation of diluted earnings per share because they were either antidilutive or the required performance or market conditions were not met. Some or all of these shares may be dilutive potential common shares in future periods.

QUARTER ENDED

YEAR-TO-DATE ENDED

SHARES IN THOUSANDS

JUNE 2022

JUNE 2021

JUNE 2022

JUNE 2021

Performance share units

573

1,142

573

1,142

On September 22, 2021, we announced that our board of directors approved a new share repurchase program (the 2021 Repurchase Program) under which we are authorized to repurchase up to $1 billion of outstanding shares. Concurrently, the board terminated the remaining repurchase authorization under the share repurchase program approved by the board in February 2019 (the 2019 Repurchase Program).

We repurchased 3,784,787 common shares for approximately $138 million under the 2021 Repurchase Program during second quarter 2022 and 6,982,462 common shares for approximately $259 million under the 2021 Repurchase Program during year-to-date 2022. As of June 30, 2022, we had remaining authorization of $668 million for future share repurchases. We did not repurchase shares during year-to-date 2021.

All common stock repurchases under the 2021 Repurchase Program were made in open-market transactions. We record share repurchases upon trade date as opposed to the settlement date when cash is disbursed. We record a liability for repurchases that have not yet been settled as of period end. There were no unsettled repurchases as of June 30, 2022, or December 31, 2021.