The average U.S. pump price for regular-grade gasoline fell 4.7 cents, or 2.1 percent, to $2.154 a gallon in the week ended Monday, the Energy Department said.
Prices have fallen for eight straight weeks.
The Rocky Mountain states saw the largest decrease in retail gasoline prices, as they fell 7 cents to $2.182 a gallon, according to the government's survey of 800 filling stations. Average gasoline costs fell the least in the Midwestern states, where they dropped 3.3 cents to $2.054 a gallon. Prices dropped in all parts of the country.
U.S. pump prices are 8.3 percent higher from the average $1.989 a gallon a year ago. The government began compiling the retail price report in 1990.