We calculate basic earnings per share (EPS) of common stock by dividing net income attributable to Cummins Inc. by the weighted-average number of common shares outstanding for the period. The calculation of diluted EPS assumes the issuance of common stock for all potentially dilutive share equivalents outstanding. We exclude shares of common stock held in the Employee Benefits Trust (EBT) (see Note 14, "SHAREHOLDERS' EQUITY") from the calculation of the weighted-average common shares outstanding until those shares are distributed from the EBT to the Retirement Savings Plan. Following are the computations for basic and diluted earnings per share:
Years ended December 31,
Dollars in millions, except per share amounts
Net income attributable to Cummins Inc.
Weighted-average common shares outstanding
Dilutive effect of stock compensation awards
Earnings per common share attributable to Cummins Inc.
The weighted-average diluted common shares outstanding excludes the anti-dilutive effect of certain stock options since such options had an exercise price in excess of the monthly average market value of our common stock. The options excluded from diluted earnings per share were as follows: