The average price of a gallon of on-highway diesel fuel showed only a slight fluctuation for the week,  barely extending a 12-week streak of dropping prices, according to the latest numbers from the U.S. Energy Department.

The price of diesel fuel dropped 0.2 cents nationally to an average of $2.615 per gallon. Prices are still much lower than last year; this week’s numbers represent a $1.22 drop from the same week in 2014.

Regional prices were down in most places, with only the Midwest market showing a slight increase during the week. The price rose 2.4 cents in the Midwest to $2.539 per gallon. The largest drop in prices was found in the New England region, falling 4.4 cents to $2.803 per gallon.

The average price of a gallon of gasoline broke ranks with diesel fuel, jumping up by 8.7 cents for the week to $2.716 per gallon.

Regional prices were up and down for the week, with a 31-cent per gallon increase in the Midwest causing the overall average increase in gasoline prices. This was offset somewhat by 4-cent decreases along the north and central portions of the East Coast.

The large jump in gas prices in the Midwest is due to the partial shutdown of a BP refinery in Indiana, according to a report in the Minneapolis Star Tribune. The shutdown was blamed on problems with the facilities crude distillation unit causing a 30- to 50-cent jump in places like Minnesota and Michigan.

Crude oil prices have continued to fall, with per barrel prices in the U.S. hitting a six-year low. A continuing concern that the global market would remain oversupplied through the end of the year has influenced low oil prices this year, according to the Wall Street Journal.