(Portland, OR) -- Gas prices in Oregon declined three cents over the last week to four-05 a gallon. Triple-A reports the national average increased three cents tthree-50. Gas prices for the 4th of July holiday are at the lowest level in three years. If Hurricane Beryl effects oil production in the Gulf of Mexico that could cause gas prices to rise. Oregon's average is 58 cents a gallon lower than this time last year.