(REGIONAL) Those gassing up their vehicles in Jackson Hole this week certainly noticed the marked increase in the price per gallon of gasoline at the pumps. Nationally, says Amerine Woodyard of the US Energy Information Administration, the price per gallon remains on a steady increase. She says the U.S. average retail price for regular gasoline rose to $3.48 a gallon on Monday. That’s up 3½¢ from a week ago, based on the weekly price survey by the U.S. Energy Information Administration. In Jackson Hole, the average of the prices surveyed by Motor Trend Magazine is $3.33 per gallon of unleaded regular, and $3.41 in Teton Valley, Idaho. Analysts say the national prices are beginning to exhibit the seasonal increase as refineries undergo their annual maintenance as they switch over to the summer blend of fuel additives required under law, which in turn reduces the amount of gasoline available during the change-over process.