Last week, gasoline prices continued their slow decline in Iowa, but diesel prices reversed course with a sizable jump. According to the Iowa Department of Agriculture and AAA-Iowa, a gallon of regular unleaded gasoline averaged $3.51 across the state as of Wednesday, Aug. 31. That is a five-cent drop from last week but still 52 cents higher than this time last year. The national average on Wednesday stood at $3.84 per gallon, down four cents from Aug. 24. Retail diesel in Iowa climbed 23 cents to $4.95 per gallon on average. That price is $1.86-higher than a year ago. Wholesale ethanol was unchanged at $2.16 per gallon. Natural gas prices dipped 11 cents at the Henry Hub reporting site to $9.16 per MMBtu.