The U.S. average on-highway price for diesel fuel dropped by a tenth of a cent to $3.907 over last week, according to the Department of Energy. The marginal decrease broke a 15-week streak in diesel price increases.

The price is up 74.5 cents since prices began to rise, and up 96.1 cents over last year.

As always, regional prices varied, with California gaining 2.9 cents per gallon to average $4.199. The Gulf Coast still claims the lowest prices at $3.841 per gallon, down a tenth of cent from last week.

This break in the upward momentum of diesel prices is likely to be only temporary. Crude oil prices climbed Monday, as energy experts warned that Libya's oil exports could be off the world market longer than expected, and countries including the U.S. enforced a no-fly zone over the country. Added to this is the general concern over unrest in North Africa and the Middle East, which produces 27 percent of the world's oil.

On Monday, Benchmark West Texas crude for May delivery gained $1.24 to settle at $103.09 per barrel on the New York Mercantile Exchange. The April contract, which ends Tuesday, rose $1.26 to settle at $102.33 per barrel. Last week, oil had slipped below the $100 mark following the earthquake in Japan.

For more information: www.eia.gov