EARNINGS PER SHARE

The following table sets forth the computation of basic and diluted earnings per share on net income (in thousands, except per share information):



	2017		2016		2015
Earnings:
Net income (numerator for basic and diluted calculations)	$	1,822,181	$	701,443	$	502,166
Shares:
Weighted average outstanding shares (denominator for basic calculations)	64,427		64,274		66,553
Equivalent shares from outstanding stock options	1,326		715		739
Diluted shares (denominator for diluted calculations)	65,753		64,989		67,292
Earnings per share:
Basic	$	28.28	$	10.91	$	7.55
Diluted	27.71		10.79		7.46

The calculation of common equivalent shares does not include the impact of options having a strike or conversion price that exceeds the average stock price for the earnings period, as the result would be antidilutive. The calculation of common equivalent shares also excludes the impact of outstanding performance contingent shares, as the conditions necessary for their issuance have not been satisfied as of the end of the reporting period. Approximately 0.2 million and 0.3 million outstanding stock options were not included in the calculation of common equivalent shares during 2017 and 2015, respectively. During 2016, all outstanding options were included in the calculation of common equivalent shares. Approximately 0.3 million, 0.4 million and 0.4 million performance contingent shares were excluded from the calculation of common equivalent shares during 2017, 2016 and 2015, respectively.