For the past two months, diesel prices have been on a steady decline. And this week is no different.This week, average U.S. diesel prices dropped 5.9 cents to $2.723 from last week’s $2.782, according to the Energy Information Administration (EIA). This week’s price is $1.135 per gallon cheaper compared to the same week last year.Diesel prices decreased in every region, with only one area breaking the $3 per gallon mark: California, down 3.9 cents to $3.072 per gallon.Average U.S. retail pump prices for gasoline decreased by 5.7 cents this week to $2.745 per gallon. According to EIA, that is 79.4 cents cheaper compared to the same week last year.Gasoline prices increased in one region this week: the Rocky Mountains, up 1.5 cents to $2.856. Only the West Coast and West Coast without California regions saw prices over $3 per gallon at $3.545 and $3.085, respectively.