(Portland, OR) -- Gas prices are declining for the second week in a row during a time of the year when prices normally rise. Crude oil is at a four-year low and demand for gas is weak. Triple-A reports that the national average price declined a penny over the last week to three-17 a gallon. Oregon's average fell a nickel to three-93. Crude oil prices are starting to rise again and that could cause gas prices to increase.