The Iowa Department of Natural Resources monthly survey found a 12-cent decline in the price of a gallon of gas last month. D-N-R analyst Ward Lenz says it was a seasonal drop due to a decrease in demand, although Lenz says the 12-cent drop was larger than expected. Lenz says self-serve unleaded gas averaged one-dollar-and-35-cents a gallon last month. The major suppliers of crude oil are talking about decreasing production, but Lenz says that shouldn’t have a big impact on prices. Lenz says any dip in gas prices will likely not last long as the world markets will remain volatile.Lenz says the national average gas price last month was one-dollar-37-cents a gallon.