Earnings Per Share

12 Months Ended

Dec. 31, 2016

Earnings per Share

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



	2016	2015	2014
Denominator for basic earnings per share—weighted-average shares	262.9	263.0	275.9
Effect of dilutive securities—employee stock options, non-vested restricted stock awards and convertible debentures	5.2	9.9	10.0
Denominator for diluted earnings per share	268.1	272.9	285.9

During the years ended December 31, 2016, 2015 and 2014, weighted-average shares related to certain stock options of 2.2, 1.0 and 0.5, respectively, were excluded from the denominator for diluted earnings per share because the stock options were anti-dilutive.

During the years ended December 31, 2016, 2015 and 2014, we issued approximately 0.5, 0.4 and 0.7 restricted stock units, respectively, of which vesting was contingent upon 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 2016 contingent restricted stock units are being measured over the three year period of 2016 through 2018 and the 2015 contingent restricted stock units are being measured over the three year period of 2015 through 2017. The 2016 and 2015 contingent restricted stock units remain contingent as of December 31, 2016. The 2014 contingent restricted stock units were based on annual targets and were subsequently included in the denominator for diluted earnings per share for the year ended December 31, 2015.

The Equity Units are potentially dilutive securities but were excluded from the denominator for diluted earnings per share for each of the years presented as the dilutive stock price threshold was not met. For additional information relating to the Equity Units, see Note 12, “Debt.”