NEW YORK (CNNMoney.com) -- Gasoline prices fell for the 20th straight day, pushing the nationwide average down more than 25 cents, according to a survey of gas station credit card swipes released Wednesday.

Regular unleaded gas fell 0.9 cent to a nationwide average of $3.862 a gallon, said motorist advocacy group AAA.

Prices hit a record high of $4.114 at the pump on July 16. Since then, gasoline - and the future contracts of crude oil - have declined on signs that high prices have caused Americans to consume less.

Still, the price of a gallon of regular gas remains more than $1 higher than it was a year ago.

Ethanol. Faced with rising fuel costs, many drivers have turned to ethanol, which is made primarily from corn and is increasingly available in regions with strong agricultural industries such as the Midwest.

The price of E85, an 85% ethanol blend that also burns cleaner than straight gasoline, fell a penny to $3.132 a gallon on average, AAA reported.

While ethanol is derived from renewable sources, it is less efficient than gasoline. As a result, a car running on E85 would pay the equivalent of $4.122 per gallon to get the same mileage as gas, the AAA survey estimated.

Diesel. The average price of diesel fuel, which is used to power most trucks and commercial vehicles, fell to $4.633 a gallon from $4.644 the previous day, according to AAA.

Diesel prices have climbed more than 56% in the last year, driving up costs for businesses and inflating the prices of the goods and services those businesses provide.

State prices. The AAA survey, which averages data from credit card swipes at 85,000 fuel stations around the country, showed that gas remains above $4 a gallon in 11 states and the District of Columbia.

Gas in Alaska, the state with the highest prices, fell to an average of $4.63 a gallon from $4.646 the previous day. Hawaii, the state with the second highest prices, saw average prices rise slightly to $4.468. California, the state in third place, saw prices slip to $4.189 on average.

In Oklahoma, the state with the cheapest gas, prices rose slightly to $3.613 a gallon. In Missouri, the next cheapest state for gas, drivers paid $3.628 on average, followed by Minnesota at $3.642 a gallon.

Drivers in Hawaii, the state with the most expensive diesel, paid $5.391 a gallon for diesel. Diesel, on average, was cheapest in Oklahoma at $4.414, according to the AAA survey.

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