According to the Iowa Department of Agriculture and AAA-Iowa, the average price for a gallon of gasoline in the state has climbed by more than a third of a dollar since last week. As of Wednesday, June 8, regular unleaded gasoline averaged $4.68. A year ago, the same gallon of gas cost $2.87 per gallon. The national average climbed to $4.96, a 29-cent rise from last week. Iowa diesel prices were up 12 cents on average to $5.29 per gallon, compared to $3.06 this time last year. Iowa diesel remains 43 cents below the national average of $5.72 per gallon. Wholesale ethanol was unchanged at $2.16 per gallon, while natural gas prices spiked $1.26 to $9.59 per MMBtu at the Henry Hub reporting site.