EXHIBIT 11 NORTHWEST NATURAL GAS COMPANY Statement re: Computation of Per Share Earnings (Thousands, except per share amounts) (Unaudited) Three Months Ended March 31, ------------------ 1997 1996 ---- ---- Earnings Applicable to Common Stock ............ $24,080 $22,665 Debenture Interest Less Taxes ............. 119 132 ------- ------- Net Income Available for Fully-Diluted Common Stock ................................. $24,199 $22,797 ======= ======= Average Common Shares Outstanding .............. 22,590 22,274 Stock Options ............................. 40 18 Convertible Debentures .................... 539 599 ------- ------- Fully-Diluted Common Shares .................... 23,169 22,891 ======= ======= Fully-Diluted Earnings per Share of Common Stock $ 1.04 $ 1.00 ======= =======