National on-highway diesel prices fell by 3.7 cents last week to average $3.749 per gallon. The pace of falling prices decelerated from the previous week's 4.7-cent drop.

Prices fell in every major region, but varied somewhat. The central Atlantic dropped the most at 4.1 cents, the Rocky Mountains the least at 2.1 cents. As usual, the Gulf Coast claimed the lowest price at $3.693 per gallon.

California, like last week, is still the only region with prices north of the four-dollar mark, but just barely at $4.007.

Oil fell to its lowest level in over a year amid fears that Greece will default on debt payments, which would slow global economic growth. Crude for November delivery lost $1.59 to land at $77.61 per barrel. Overall, prices have dropped 15% this year.

Greece said it passed a new budget on Monday backed by its international creditors. While the budget included larger deficits than previously forecast, the financially embattled country did inch closer to securing the $10.7 billion bail out necessary to pull it back from the brink.