Diesel prices are down again this week, according to the most recent data from the Energy Information Administration (EIA).This week, diesel is down 1.7 cents to $2.476 from last week’s $2.493. This week’s price is $1.279 cheaper than the same week last year, EIA said. Diesel dipped in every region this week – with all regions remaining under the $3-per-gallon mark. The most significant drop was a 3.6-cent decrease in the Rocky Mountain region – down to $2.486 from last week’s $2.522.Average U.S. retail pump prices for gasoline were down slightly, slipping by only 5 tenths of a cent to $2.322 from last week’s $2.327, according to EIA. That is $1.032-per-gallon less than the same week last year. Gas prices are down in all but two regions this week – the Lower Atlantic, which is up 6 tenths of a cent to $2.113 from last week’s $2.107, and the Midwest, which increased 5.4 cents to $2.325 from last week’s $2.271. All regions remain under the $3-per-gallon mark.