Gasoline Prices Tumble further

NEW YORK (CNNMoney.com) -- Gas prices continued their slide, falling 11% from highs reached in July, according to a national survey of gas station credit card swipes released Thursday.

Gas was selling at $3.660 a gallon, a decrease of seven tenths of a cent from the previous day's price of $3.667, according to motorist group AAA and the Oil Price Information Service. Thursday's decline is the fifth consecutive day that retail gas prices have fallen.

Prices have fallen more than 45.4 cents since hitting a record of $4.114 on July 17, AAA reported.

The average price of a gallon of gas has been falling as crude oil prices have come sharply off their recent highs. Crude futures hit a record high of $147.27 on July 11 but have since fallen more than 18% as global demand slackened in reaction to the high energy costs.

While gas prices have fallen off their recent highs, however, prices at the pump are still 33% above the same time last year, when a gallon of gas cost $2.758.

State prices: Gas prices change from one state to the next due to differences in state and local gasoline taxes. In addition, gas prices vary by state according to how far the state is from oil and gas facilities in the Gulf of Mexico.

Gasoline remains above $4 a gallon in only two states, according to the survey. Alaska had the highest prices at $4.529 a gallon, down slightly from the previous day's price of $4.546. Hawaii was second at $4.386, down from $4.393 yesterday.

Missouri had the cheapest gas, with prices falling to $3.424 a gallon. South Carolina had the second least expensive gas, with a gallon costing $3.442.

Diesel: The average price for diesel fuel, which is used in most trucks and commercial vehicles, fell to $4.275 a gallon from $4.283 the previous day, according to AAA.

The price of diesel has risen almost 46% in the last year, when a gallon of diesel cost $2.930. Because it is used in transporting goods, the rise in the price of diesel fuel has pushed up the prices of products and services.

Ethanol: Many Americans have turned "flex-fuel" vehicles powered in part by ethanol as the price of petroleum-based fuels climbed to record levels in the past year.

The price of E85, an 85% ethanol blend, fell to $3.009 a gallon on average from $3.030 in the previous day, AAA reported.

Ethanol, made out of corn, is cheaper than regular gas, which is made from pricey crude oil. However, ethanol is only readily available in the Midwest, where much of the nation's corn is produced,and it's not even sold in some states.

Ethanol contains less energy than petroleum-based gasoline and burns less efficiently. Drivers of vehicles capable of running on ethanol or gasoline would pay about $3.959 a gallon to get the same mileage from ethanol as from regular gas, according to AAA's estimates