The average price of a gallon of gas is up seven cents in the latest survey — but prices have stayed below the national average. Don Tormey of the Iowa Office of Energy Independence says summer driving has had some impact on the prices. Tormey says the gas prices seem to follow the stock market and oil markets and there’s been a slight increase in demand with the summer driving.

But overall, he says the prices have stayed pretty stable. The average cost of a gallon of ethanol-blended gas was $2.58, which is 10-percent higher than last year at this time. Tormey says the summer driving impact will be around for a few more weeks.

He says the summer driving season usually lasts through August and the state fair and the start up of school, then driving tends to drop off. The cost of diesel fuel went down a penny in the latest survey, with average cost for a gallon of diesel at two-dollars and 89 cents a gallon.