Gas price decline: Day 29
The price of regular gasoline falls to $3.771 a gallon at the pump, according to a daily survey from AAA.
NEW YORK (CNNMoney.com) -- Gasoline prices fell slightly for the 29th straight day, a daily survey of gas station credit card swipes revealed Friday.
The price of regular unleaded gasoline at the pump fell seven-tenths of a cent to a nationwide average of $3.771 a gallon, according to the Daily Fuel Gauge Report from motorist advocacy group AAA and the Oil Price Information Service.
Prices have fallen since hitting a record high of $4.114 a gallon on July 16, mirroring a decline in crude futures.
However, gas prices remain more than $1 higher than a year ago. High fuel prices helped drive inflation to an annual rate of 5.6% in July - the highest in 17 years.
Ethanol: The high price of petroleum-based fuel has prompted many drivers to turn to ethanol, which is made primarily from corn.
The price of E85, an 85% ethanol blend, fell to $3.049 a gallon on average from $3.053, AAA reported.
Ethanol burns cleaner than gasoline but has a lower energy content and burns less efficiently in flex fuel vehicles. According to AAA's estimates, a vehicle that burns E85 would pay about $4.012 a gallon to get the same mileage as gas.
Diesel: The average price for diesel fuel, which is used in most trucks and commercial vehicles, fell to $4.445 a gallon from $4.47 the day before, according to AAA.
The price of diesel has risen more than 51% over the past 12 months. Because of its use in transporting goods, high priced diesel can help drive up the prices of products and services.
State prices: AAA, which bases its survey on credit card swipes at up to 100,000 fuel stations around the country, found that gas remains above $4 a gallon in only six states.
Drivers in Alaska, the state with the highest prices, saw gas prices fall to $4.608 a gallon from $4.629 a day earlier. Drivers in Hawaii, the state with the second-highest prices, saw average prices rise slightly to $4.448 from $4.444. Of the lower 48 states, drivers in Utah paid the most for gas at a state average of $4.073 a gallon.
Missouri had the cheapest gas, with prices falling slightly to $3.525 a gallon from $3.528. Prices in South Carolina were the second lowest at $3.551 on average, AAA found.
Drivers in Hawaii, the state with the most expensive diesel, paid an average of $5.365 a gallon for diesel. Diesel was cheapest in Missouri, where prices fell to an average of $4.166. 
