Gas drop: 18 days and counting
The average price of regular gas falls to $3.881 a gallon, according to national survey.
NEW YORK (CNNMoney.com) -- Retail gas prices fell for the 18th straight day, extending their multi-week slide, a daily survey of gas station credit card swipes showed Monday.
Gasoline: Regular unleaded gas fell 0.6 cents to a nationwide average price of $3.881 a gallon, according to a survey from motorist advocacy group AAA.
The average price for regular has fallen more than 23 cents since hitting a record high of $4.114 at the pump on July 16, according to AAA data, following a steep drop in crude oil prices.
However, the price of regular gas remains more than $1 a gallon more than it was a year ago, and nearly three quarters of Americans say high prices have become a financial burden, according to a CNN/Opinion Research poll released Friday.
Ethanol: Ethanol prices turned slightly higher on Monday.
High gas prices have caused many drivers, particularly those in regions with strong agricultural industries such as the Midwest, to switch to ethanol as their fuel of choice.
The price of E85, an 85% ethanol blend which burns cleaner than straight gasoline and is made primarily from corn, rose 0.2 cents to $3.125 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 $4.113 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 $4.654 a gallon from $4.665 the previous day, according to AAA.
Diesel prices have climbed more than 57% in the last 12 months, 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 remained above $4 a gallon in 12 states.
Gas in Alaska, the state with the highest prices, rose to an average of $4.647 a gallon from $4.645 the previous day. Hawaii, the state with the second highest prices, saw average prices fall to $4.451. California, the state in third place, saw prices slip to $4.21 on average.
Drivers in Oklahoma, the state with the cheapest gas, saw prices fall to $3.611 from $3.615 a gallon the day before. In Missouri, the next cheapest state for gas, drivers paid $3.636 on average, followed by Minnesota at $3.65 a gallon.
Drivers in Hawaii, the state with the most expensive diesel, saw diesel prices fall to $5.381 a gallon. Diesel, on average, was cheapest in Oklahoma at $4.43, according to the AAA survey. 
