15.   Net income per common share

The following is a reconciliation of net income and the number of shares of common stock used in the computation of net income per basic and diluted common share:

The denominator for diluted net income per common share for fiscal years 2018,  2017 and 2016 excludes 302,  167, and 142 employee stock options and restricted stock units, respectively, due to their anti-dilutive effects. Outstanding performance-based restricted stock units are included in the computation of dilutive shares only to the extent that the underlying performance conditions are satisfied prior to the end of the reporting period or would be considered satisfied if the end of the reporting period were the end of the related contingency period and the results would be dilutive under the treasury stock method.