PETROLEUM DEVELOPMENT CORPORATION AND SUBSIDIARIES EXHIBIT 11 SCHEDULE OF COMPUTATION OF NET INCOME PER SHARE Years Ended December 31, BASIC 1999 1998 1997 Net income for basic income per common share $ 7,824,300 6,658,000 7,586,800 Weighted average number of common shares outstanding during the year 15,734,063 15,505,680 11,278,800 Basic earnings per share $ .50 $ .43 $ .67 DILUTED Net income for basic earnings per common share $ 7,824,300 6,658,000 $ 7,586,800 Net income for diluted earnings per share $ 7,824,300 6,658,000 $ 7,586,800 Weighted average number of shares used in calculating basic earnings per common share 15,734,063 15,505,680 11,278,800 Shares issuable for diluted calculation 552,789 832,618 1,261,365 Weighted average number of shares used in calculation of diluted earnings per share 16,286,852 16,338,298 12,540,165 Diluted earnings per share $ .48 $ .41 $ .61