Gas prices hit all-time high
National average price keeps climbing - up more than a third in price from a year ago.
NEW YORK (CNNMoney.com) -- Gasoline prices hit yet another record Sunday, with more than half the nation's states paying more than $4 per gallon on average, according to a daily survey from motorist group AAA.
The national average price for regular unleaded gasoline climbed slightly to $4.077 a gallon, according to AAA's Web site.
The average topped $4 for the first time last week after crude oil prices surged to a trading record above $139 per barrel. The price has swung back and forth in a $10 range since then.
Gas is most expensive in California, according to the survey, averaging $4.597, followed by Alaska at $4.436.
Missouri has the lowest average price at $3.834, followed by Oklahoma at $3.846.
Gasoline prices in the survey have risen 35 percent from a year ago when they averaged $3.018.
On its Web site, AAA says the information is gathered by Oil Price Information Service based on credit card swipes at 85,000 gasoline stations across the nation. 
