UPDATED -- The average cost of on-highway diesel has moved lower once again, shedding 2.3 cents from a week ago and hitting it lowest price since mid-July of 2012.

It clocked in at $3.778 per gallon this week, according to the U.S. Energy Department, marking the 12th straight week without an increase. Compared to the same time last year, the average cost of diesel is down 17.1 cents.

The last time diesel moved higher was on June 30 when it hit $3.92 and has moved lower every week since, except when the weekly average was unchanged for one week early this month.

Prices fell by at least a penny in all parts of the country over the past week and range from a low of $3.696 in the Gulf Coast region, which had the smallest decline, to a high of $3.99 in the West Coast region, where it declined 2.9 cents. The price in California, the one state DOE tracks separately, was slightly higher at $4.401, down 2.2 cents from a week ago.

Regular-grade gasoline also posted a decline, falling 5.5 cents from last week for an average of $3.353 per gallon, marking its lowest price since early February. Compared to a year ago it is 14.2 cents lower.

Prices for gasoline fell in all parts of the country with it ranging from a low of $3.127 in the Gulf Coast states to a high of $3.683 in the West Coast region. Prices are also down in all regions compared to this time in 2013, by at least 4.2 cents.

The drops happened as the price of oil also fell, losing 89 cents by the end of trading Monday in New York, settling at $91.52 per barrel. Compared to last Tuesday’s opening price it is down $1.29 due to a stronger dollar, sluggish world demand and increasing U.S. stockpiles.

Updated adds gasoline prices.