It was a mixed bag for Iowa fuel prices in the latest report from the Iowa Department of Agriculture and AAA-Iowa. As of Wednesday, May 24, the price of regular unleaded gasoline averaged $3.41 per gallon, a six-cent increase from the prior week and 76 cents lower than a year ago. The national average for gasoline on Wednesday stood at $3.56 per gallon, a three-cent increase. Retail diesel prices fell three cents on the week to $3.73 per gallon, compared to $5.21 per gallon this same time last year. Nationally, diesel prices averaged $3.99 per gallon. Wholesale ethanol was unchanged from $2.16, and natural gas prices at the Henry Hub reporting site climbed 19 cents to $2.54 per MMBtu.