PETROLEUM DEVELOPMENT CORPORATION AND SUBSIDIARIES EXHIBIT 11 SCHEDULE OF COMPUTATION OF NET INCOME PER SHARE Years Ended December 31, BASIC 1998 1997 1996 Net income for basic income per common share $6,658,000 7,586,800 3,549,400 Weighted average number of common shares outstanding during the year 15,505,680 11,278,800 10,449,137 Basic earnings per share $ .43 $ .67 $ .34 DILUTED Net income for basic earnings per common share $ 6,658,000 $ 7,586,800 $ 3,549,400 Net income for diluted earnings per share $ 6,658,000 $ 7,586,800 $ 3,549,400 Weighted average number of shares used in calculating basic earnings per common share 15,505,680 11,278,800 10,449,137 Shares issuable for diluted calculation 832,618 1,261,365 1,093,178 Weighted average number of shares used in calculation of diluted earnings per share 16,338,298 12,540,165 11,542,315 Diluted earnings per share $ .41 $ .61 $ .31 E-2