EXHIBIT 11 NORTHWEST NATURAL GAS COMPANY Statement re: Computation of Per Share Earnings (Thousands, Except Per Share Amounts) Three Months Ended Nine Months Ended Sept. 30, Sept. 30, 2000 1999 2000 1999 ------------------- --------------------- Earnings (Loss) Applicable to Common Stock $ (5,489) $ (4,183) $ 27,392 $ 29,374 Debenture Interest Less Taxes 100 105 299 315 -------- -------- --------- --------- Net Income (Loss) Available for Diluted Common Stock $ (5,389) $ (4,078) $ 27,691 $ 29,689 ======== ======== ========= ========= Average Common Shares Outstanding 25,203 25,007 25,175 24,946 Stock Options 29 31 8 15 Convertible Debentures 453 476 453 476 -------- -------- --------- --------- Diluted Common Shares 25,685 25,514 25,636 25,437 ======== ======== ========= ========= Diluted Earnings (Loss) Per Share of Common Stock $ (0.22) $ (0.17) $ 1.08 $ 1.17 ======== ======== ========= =========