The average price of a gallon of diesel dropped for the second week in a row, but only by a less than a penny, according to weekly figures released Monday by the U.S. Department of Energy.

The DOE's Energy Information Administration reports a national average price for retail on-highway diesel of $3.162, down just under a penny from last week's $3.171. That's 38.7 cents higher than the same week a year ago.

The highest prices were reported in the West Coast region, with an average of $3.30, down 1.6 cents from the previous week. It was followed closely by the Central Atlantic region at $3.288 and the Rocky Mountain region at $3.272. Prices rose slightly in the New England and Rocky Mountain regions but dropped in all other regions.

The lowest prices were reported in the Gulf Coast region at $3.078.

Meanwhile, crude oil futures surpassed $85 a barrel Monday to settle at $85.73 a barrel on the New York Mercantile Exchange, the highest price in two weeks. This was despite a stronger dollar; usually, a weaker dollar compared to other currencies sends investors into commodities such as oil.

The dollar apparently was pushed out by colder-than-normal temperatures and heating demand in Europe and news of a strong "Black Friday" in the U.S. brought hope of a revival in consumer spending. Reuters reported that expectations that strong online gift buying could boost demand for delivery transportation had some analysts pointing to improving fundamentals. In addition, the Energy Information Administration revised September U.S. oil demand upward.