Diesel prices have hit their highest level since September 2008.

The U.S. Energy Information Administration reported on Monday that the national average price for a gallon of diesel is $4.15, up 5.6 cents a gallon from last week, and 34.9 cents from one year ago. The last time we saw similar prices was in August 25, 2008 when the fuel was at $4.15 on its way down from a high of $4.77 reached in July '08.

According to the department of energy, prices around the country last week ranges from a low of $4.02 in the gulf coast region to a high of $4.36 on the west coast. Elsewhere, east coast prices averaged $4.13 per gallon, the Midwest saw an average of $4.15, while the rocky mountain states paid as much as $4.27 a gallon.

Gasoline, on the other hand, has been experiencing a slow decrease in prices. Nationally, the price for a gallon of gasoline fell 3.1 cents. On average, the price for a gallon of gasoline settled at $3.82. The least expensive gasoline prices can be found on the Gulf Coast where the average price for a gallon of gasoline costs $3.54.

Oil prices have held at around $92 for the past week. In trading on Monday, benchmark crude finished down a penny at $91.85 a barrel in New York.