Gas prices slip, nearing $4
Fuel prices fall for 8th day in a row to a level not seen since early June.
NEW YORK (CNNMoney.com) -- Gas prices declined for the 8th straight day, nearing a level not seen in seven weeks, according to a nationwide survey Friday of filling station credit card swipes. Other fuel prices also continued to fall.
Gasoline: The price of regular unleaded gasoline at the pump slipped 2 cents to $4.006 a gallon on average, a daily survey from motorist advocacy group AAA revealed.
Sky-high fuel prices have been responsible for much of the strain on American consumers and businesses, making transportation and shipping more expensive, while economic problems and falling home values have sapped the value of property and investments.
Average gasoline prices first crossed the $4 mark on June 7 when they hit $4.005 a gallon, according to the AAA surveys.
Subsequently, the rising cost of crude oil, which has ballooned more than 70% over the last 12 months, sent gasoline prices to a record high of $4.114 on July 16.
Prices stayed there for two days before starting to retreat, following a double-digit decline in oil as investors worried that the high cost of fuel was leading to a slowdown in demand.
Ethanol: High fuel prices have caused many drivers, particularly those in states with strong agricultural industries, to switch to ethanol as their fuel of choice.
The price of E85, an 85% ethanol blend, which burns cleaner than pure gasoline and is made primarily from corn, fell a penny to $3.238 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 $4.262 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 as well to $4.774 a gallon from $4.788, according to the AAA survey.
Diesel remains more than 60% higher than last year. And because of its use in transporting goods, high prices for diesel have affected the prices of other items.
State prices: The AAA survey averages data from credit card swipes at 85,000 fuel stations around the country. The survey found that the number of states that suffer from gas prices above $4 a gallon fell to 20 on Friday.
Gas in Alaska, the state with the highest prices, fell to $4.68 a gallon from $4.695 the day before. Hawaii, the state with the second highest prices, saw average prices climb to $4.49. California prices dipped to $4.374 on average, the survey said.
Drivers in Oklahoma, the state with the cheapest gas, saw prices fall to $3.769 from $3.793 a gallon. In Missouri, the next cheapest state for gas, drivers paid $3.799 on average, followed by Minnesota at $3.791.
Drivers in Hawaii, the state with the most expensive diesel, saw prices fall to $5.41 a gallon, while diesel was cheapest in Oklahoma at $4.567. 
