Dunbar Company had 470,000 shares of common stock outstanding during the year 2015. In addition, at December 31, 2015, 73,000 shares were issuable upon exercise of executive stock options which require a $40 cash payment upon exercise (options granted in 2015). The average market price during 2015 was $50. Compute the number of shares to be used in determining diluted earnings per share for 2015.