Petrol prices in the United States fell again last week, dipping 18 cents a gallon.
The Energy Information Administration said on Monday that the national average retail price for regular, self-service petrol dropped to $US2.22 in the week ended on Monday, down from $US2.40 the previous week.
The average price of petrol is 89 cents lower than it was a year ago.
The average price of gasoline fell in every region of the country including California, which generally has the highest fuel costs.
Separately, the average price for diesel fuel fell 14.4c to $US2.94 a gallon, down 48.1c from a year ago.
