EXHIBIT 11 NORTHWEST NATURAL GAS COMPANY Statement re: Computation of Per Share Earnings (Thousands, except per share amounts) (Unaudited) Three Months Ended March 31, ----------------------- 2001 2000 ----------------------- Earnings Applicable to Common Stock $ 25,299 $ 31,040 Debenture Interest Less Taxes 96 103 --------- --------- Net Income Available for Diluted Common Stock $ 25,395 $ 31,143 ========= ========= Average Common Shares Outstanding 25,207 25,129 Stock Options 41 - Convertible Debentures 435 466 --------- --------- Diluted Common Shares 25,683 25,595 ========= ========= Diluted Earnings per Share of Common Stock $ 0.99 $ 1.22 ========= =========