Earnings Per Share

12 Months Ended

Dec. 31, 2022

Earnings per Share

The denominator for basic and diluted earnings per share at December 31, 2022, 2021 and 2020 is as follows:


	2022	2021	2020
Denominator for basic earnings per share—weighted-average shares	240.0	243.8	250.8
Effect of dilutive securities—employee stock options, non-vested restricted stock awards, convertible debentures and equity units	2.8	3.0	3.5
Denominator for diluted earnings per share	242.8	246.8	254.3

During the years ended December 31, 2022, 2021 and 2020, weighted-average shares related to certain stock options of 0.4, 0.2 and 1.2, respectively, were excluded from the denominator for diluted earnings per share because the stock options were anti-dilutive.

During the years ended December 31, 2022, 2021 and 2020, we issued approximately 0.2, 0.3 and 0.3 restricted stock units, respectively, of which vesting was contingent upon us meeting certain earnings targets. Contingent restricted stock units are excluded from the denominator for diluted earnings per share and are included only if and when the contingency is met. The 2022 contingent restricted stock units are being measured over the three year period of 2022 through 2024, the 2021 contingent restricted stock units are being measured over the three year period of 2021 through 2023 and the 2020 contingent restricted stock units are being measured over the three year period of 2020 through 2022. Contingent restricted stock units generally vest in March of the year following each measurement period.