EXHIBIT 11 NORTHWEST NATURAL GAS COMPANY Statement re: Computation of Per Share Earnings (Thousands, except per share amounts) (Unaudited) Three Months Ended Six Months Ended June 30, June 30, ------------------- ----------------- 1997 1996 1997 1996 ---- ---- ---- ---- Earnings Applicable to Common Stock $1,694 $4,823 $25,774 $27,488 Debenture Interest Less Taxes 117 127 234 254 ------ ------ ------- ------- Net Income Available for Fully-Diluted Common Stock $1,811 $4,950 $26,008 $27,742 ====== ====== ======= ======= Average Common Shares Outstanding 22,661 22,343 22,625 22,309 Stock Options 49 33 49 33 Convertible Debentures 533 578 533 578 ------ ------ ------- ------- Fully-Diluted Common Shares 23,243 22,954 23,207 22,920 ====== ====== ======= ======= Fully-Diluted Earnings per Share of Common Stock $0.08* $0.22 $1.12 $1.21 ====== ====== ======= ======= * Anti-dilutive