(Portland, OR)  --  Portland-area gasoline prices are down slightly from a week ago. Triple-A reports the average price for a gallon of regular grade fuel today is two-dollars-74-cents, down a penny from a week ago and two cents lower than a month ago.  Last year at this time, Portland gas cost two-47 a gallon, on average.  Currently, the nationwide average price is two-dollars-36-cents a gallon.