The price for a gallon of regular gasoline rose by four cents last week to post a national average price of $2.43 a gallon. The increase marks the third straight week of rising pump prices.

The most common pump price for a gallon of regular gasoline is $2.19 a gallon, down from $2.29 a week ago. The number of service stations selling gas for less than $2.00 a gallon dropped from more than 4,200 to just 410, according to GasBuddy. On January 9, 44% of U.S. gas stations were selling gasoline for less than $2.00 a gallon.

Patrick DeHaan, GasBuddy’s head of petroleum analysis, commented:

Gas prices continued to heat up across much of the country over the last week as every area of the country has now started the first step in transitioning to summer gasoline at the same time refiners continue maintenance. Looking at macroeconomics, rumors of a U.S.-China trade deal may push oil prices higher as it would likely lead to increasing economic growth rates in both countries and pushing demand for oil higher. Since gas prices bottomed out nearly two months ago, average gas prices are up 20 cents. We may see another 20 cent hike or so over the next two months, or perhaps greater if there are any refinery kinks that arise. We’ll still be in good shape for summer gas prices to be under their year-ago levels, so all is not lost.

Crude oil prices dipped by nearly $1.50 a barrel last week, and pump prices, which routinely reflect rising oil prices more quickly than they reflect falling crude prices, rose a couple of pennies less than they did in the prior week.

States where gas prices were lowest included Arkansas ($2.177), Missouri ($2.180) and Mississippi ($2.183). The nation’s highest prices were found in California ($3.312), Hawaii ($3.251) and Alaska ($2.823).

Pump prices are about 15 cents a gallon higher than they were last month and about 10 cents lower than a year ago.

Benchmark West Texas Intermediate crude oil for April delivery traded up about 1.4% late Monday morning at $56.58, while Brent for May delivery traded at $65.75, up about 1%. The price differential (spread) between front-month WTI and Brent crude is now around $9.17 a barrel, down about 38 cents over the past week.