Diesel prices continued their slow fall for the fourth week in a row, slipping about a penny this week to average $2.775

, according to the U.S. Department of Energy. Over the last four weeks, trucking's main fuel has dropped 3.3 cents.

Prior to the declines, diesel prices had gained 22.6 cents. This week's reading is about 16 cents higher than the same week last year, when it was $2.615.

In California, prices averaged as high as $2.948. Other areas where prices were high included the Central Atlantic and West Coast regions, where it averaged $2.90 and $2.888, respectively. The lowest prices were found in the Gulf Coast and Lower Atlantic regions, at $2.724 and $2.738, respectively.

Gasoline was also down about a penny this week, averaging $2.629. This was about 81.8 cents higher than the price during the same week last year.

Meanwhile, crude oil jumped $1.40 Monday, ending at $77.45 a barrel on the New York Mercantile exchange, according to the Associated Press. Crude prices went up on news of Iranian naval vessels seizing a racing yacht with five U.K. nationals, the AP says.