On-highway diesel prices resumed their decline last week after a slight uptick the previous week.

Nationally, prices came down 0.4 cents to land at $3.95 per gallon. The small decrease did not make up for the previous week's bump of 1.4 cents, but is perhaps an indication of price stabilization.

Prices dropped or remained unchanged in every major region of the United States. California was most expensive at $4.236. The Gulf Coast was cheapest at $3.896, a difference of 34 cents.

Oil leveled off Monday with investors still concerned about the European financial crisis.

Benchmark crude for July delivery gained 25 cents to settle at $93.26 per barrel on the New York Mercantile Exchange. The July contract expires on Tuesday, and most of the trading switched to the August contract, which added 23 cents to settle at $93.63 per barrel.

All eyes remain on Greece, which is trying to implement tough new austerity measures necessary to keep international aid coming to deal with its debt crisis. Without that aid, investors worry that Greece's financial troubles could spread to other European countries.