After months of decreasing gas prices, Iowans saw an unwelcome jump at the pump over the past week. According to the Iowa Department of Agriculture and AAA-Iowa, the average cost for a gallon of regular unleaded gasoline in the state rose 12 cents to $2.87 per gallon. The state’s prices remain 46 cents below the average for this time last year. The national average on Wednesday saw a more minor increase, climbing to $3.14 from $3.10. Retail diesel prices dropped two cents to $3.57 per gallon, compared to $4.30 a year ago. The national average stands 37 cents higher than Iowa at $3.94. Wholesale ethanol held steady at $2.16. In heating fuels, propane prices climbed one cent to $1.58 per gallon, home heating oil dropped four cents to $2.97 per gallon, and natural gas at the Henry Hub reporting site plunged 53 cents to $2.12 per MMBtu.