According to a survey by the U.S. Department of Energy (DOE), the price of diesel fuel fell by 1.4 cents per gallon to a national average of $1.286 during the week of June 2–8. Diesel is the primary fuel used by the trucking industry. The report noted that the other major fuel used in the trucking industry, gasoline, also fell in the same week by 1.7 cents per gallon, to a national average of $1.375. The report went on to say that it was the largest drop since the price fell by 1.9 cents on Dec. 3, 2001. This brought the retail price to its lowest level since March 25, when the average stood at $1.281 per gallon. Diesel prices slipped in each of the geographic regions that the DOE surveys, with the largest decline being a 2.2-cent fall in the Midwest that pushed prices to $1.261 per gallon. The survey covers about 350 filling stations nationwide to determine the average retail prices.