EXHIBIT 11 NORTHWEST NATURAL GAS COMPANY Statement re: Computation of Per Share Earnings (Thousands, except per share amounts) (Unaudited) Three Months Ended March 31, -------------------------- 2000 1999 -------------------------- Earnings Applicable to Common Stock $ 31,040 $ 23,406 Debenture Interest Less Taxes 103 107 ----------- ----------- Net Income Available for Diluted Common Stock $ 31,143 $ 23,513 =========== =========== Average Common Shares Outstanding 25,129 24,883 Stock Options * 19 Convertible Debentures 466 487 ----------- ----------- Diluted Common Shares 25,595 25,389 =========== =========== Diluted Earnings per Share of Common Stock $ 1.22 $ 0.93 =========== =========== * Anti-dilutive, not included in calculation