We have adopted the provisions of ASC 260, “Earnings Per Share,” requiring presentation of both basic and diluted earnings per share. A reconciliation of the numerators and denominators of the basic and diluted per share calculations is presented below (in thousands, except per share amounts):

 

 

 

We had 267,500 shares, 544,999 shares and 779,999 shares of common stock potentially issuable upon exercise of employee stock options for years ended December 31, 2015, 2014 and 2013, respectively, that were excluded from the weighted average number of shares outstanding on a diluted basis because the effect of such options would be anti-dilutive. These instruments expire at varying times from 2016 to 2021.