A prediction last month that gas prices would fall has proven accurate in the latest Iowa Department of Natural Resources survey. The price of gas hit its second-highest monthly average in Iowa history in the survey released May 15th. D-N-R fuels analyst David Downing at the time predicted the increase wouldn’t last. The latest survey confirms his prediction as the average price of a gallon of unleaded fell 20 cents to a-dollar-fifty-five, which is 22 cents lower than last year. Downing’s predicting steady or slightly lower prices for the rest of the summer as supplies appear strong. Iowa’s gas price puts the state slightly below the regional average of a dollar-63-cents a gallon, and slightly above the national average of a dollar-52-cents a gallon.