The national average retail diesel price fell 5.3 cents to $4.004 for the week ended Monday, May 14.
The average diesel price dropped 1.2 cents per gallon from last week and is down 5.1 cents from the same week in 2011.
For the first time since 2009, the average diesel price is lower than it was during the same week the year before.
A week after diesel prices dipped for the first time in nine weeks, the national average price of diesel rose once again.
Prices have increased every week but one since Jan. 9 and are the highest point since Aug. 25, 2008.
The current price is the highest since Aug. 25, 2008, when it was $4.158 a gallon.
The price increased 2.9 cents in the most recent period and 27.5 cents over the last seven weeks.
The latest price rocketed past $4 a gallon to $4.051. A year ago it was 33.5 cents higher.
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