For the ninth straight day, U.S. gas prices reached a record high Wednesday, adding to Americans’ inflation concerns.

According to auto club AAA, the average price for a regular gallon of gasoline in the U.S. was $4.567 Wednesday, up about four and a half cents from the day before.

On Tuesday, for the first time, the average price in all 50 states surpassed $4. Georgia, Kansas and Oklahoma had remained below that mark.

Gas is cheapest in Kansas ($4.026) and Oklahoma ($4.03), while drivers in California are paying the most, $6.05 for regular fuel on average. The cost is over $5 a gallon in Alaska, Hawaii, Nevada, Oregon and Washington.

Americans are paying 16 cents a gallon more than they were last week, 48 cents more than a month ago and $1.52 more than a year ago.

Meanwhile, diesel also is at a record high of $5.577, making shipping items by trucks more expensive.

Gas prices, however, remain below the record when adjusted for inflation, which, according to the U.S. Energy Information Administration, would be $5.38 a gallon. The current record was set in June 2008.

There are a number of reasons for the high prices. There has been greater demand as Americans emerge from the worst of the COVID-19 pandemic, and supply has not been able to keep up, due in part by the Russia-Ukraine war and the U.S. ban on Russian oil imports. Domestic production also has not returned to its pre-pandemic levels.

As long as crude oil prices remain high, so will gasoline prices, experts say. The average U.S. price for a barrel of crude Wednesday morning was nearly $114, up from a $112.40 close Tuesday.

Adding to matters, gas stations are transitioning to their summer blend of gasoline, which adds 7 to 10 cents per gallon. The annual change is done to prevent excessive evaporation when temperatures rise.

In a blog post Monday, Patrick De Haan, head of petroleum analysis at GasBuddy, said prices are likely to rise even higher. 

“Prices later this week could be closer to $5 per gallon than $4, as demand continues to edge higher and inventories of both gasoline and diesel continue to decline, temperatures warm and motorists get back outside and we near the Memorial Day weekend, the start of the summer driving season,” he wrote. “While the increases may start to slow in the days ahead as pump prices catch up to oil, there isn’t much reason to be optimistic that we’ll see a plunge any time soon.”