NORTHWEST NATURAL GAS CO <NWNG.O> 1ST QTR NET shr 1.35 dlrs vs 1.27 dlrs div 39 cts vs 39 cts prior net 14,291,000 vs 13,211,000 revs 52.6 mln vs 51.1 mln avg shrs 10,234,000 vs 9,936,000