Fuel price movement in Iowa was mixed over the last seven days, according to the latest fuel report from the Iowa Department of Agriculture and AAA-Iowa. As of Tuesday, Aug. 15, the average price for a gallon of regular unleaded gasoline was $3.77 across the state, three cents below last week’s price and 20 cents higher than a year ago. The national average on Tuesday climbed three cents to $3.86 per gallon. In retail diesel, the statewide average rose eight cents to $4.13. Iowa prices remained 20 cents below the $4.33 national average and 58 cents under prices from a year ago. Wholesale ethanol held steady at $2.16. Natural gas prices at the Henry Hub reporting site plunged 24 cents to $2.69 per MMBtu. Heating oil and propane price reporting will resume in September.