( CNN ) -- Gasoline prices have jumped another nickel , to 55 cents a gallon more than a year ago , according to a study published Sunday . The average price for a gallon of regular is $ 3.18 , the Lundberg Survey found . That 's up 5 cents from two weeks ago , publisher Trilby Lundberg said . `` That is a significant bite for motorists considering the continued deep unemployment , '' Lundberg said . And it comes amid a `` very wide and deep glut of gasoline supply , '' she added . The spike is partly due to events in the Middle East and north Africa , Lundberg said . The most common benchmark for crude oil is West Texas Intermediate on the futures market . That crude is `` glutted , in serious oversupply , '' she said . `` But U.S. refiners use many other crudes , some of which have been jumping on Middle East tensions . '' The gasoline glut has helped prevent prices from rising even more , she said . Gas prices may rise another nickel or dime in the coming weeks , Lundberg said . `` It would of course be far more if Middle East problems augmented and caused oil prices to skyrocket , '' she said . Prices at the pump have risen 49 cents a gallon since late September . The Lundberg Survey tallies average gas prices at thousands of gas stations nationwide . Here are the latest average prices in some U.S. cities : . -Billings , Montana - $ 2.95 . -San Francisco - $ 3.54 . -Houston - $ 2.98 . -St. Louis - $ 2.99 . -Tulsa , Oklahoma - $ 3.01 . -Baltimore - $ 3.09 . -Atlanta - $ 3.11 . -Boston - $ 3.21 . -Las Vegas - $ 3.20 . -Minneapolis - $ 3.18 .
Middle East tensions are behind the increase , the data says . They have risen 49 cents since March .