The average cost of a gallon of on-highway diesel fuel dropped again this week, moving lower for the second time in more than a month, according to the U.S. Energy Department.

The average price fell by 0.025 cents compared with last week to $2.884 per gallon. Prices are down $1.008 per gallon compared with this week a year ago.

Diesel prices had been increasing steadily since mid-April before peaking on May 25th at $2.914 per gallon. Since that time, the price of diesel fuel has dropped for two consecutive weeks.

By region, the largest average decline was seen on the West Coast with a 0.054-cent decline and the slightest decline was in the Rocky Mountains at 0.010 cents per gallon for prices of $3.121 and $2.825 respectively. The highest average price was predictably in California at $3.217 per gallon.

Gasoline prices fluctuated by region with the overall average price of regular grade gasoline staying flat for the week at $2.78 per gallon. Until this week, gas prices had increased for seven straight weeks and last week hit its highest level since November 2014. Despite the increases, the overall average price is still .894 cents lower than year ago levels.

The largest increase in gasoline prices took place in the Gulf Coast region at .053 cents while he largest decrease was seen in the West Coast at .067 cents for prices of $2.536 and $3.377 per gallon respectively.

Last week, OPEC decided against cutting oil production which should continue to keep prices low for the foreseeable future. Because of the move, per-barrel prices could fall into $50 territory again.  This week, prices on the New York Mercantile Exchange settled at $58.14 per barrel on news of softened demand in China.