The average retail price of a gallon of gasoline in the U.S. has dropped 2.03 cents in the last two weeks, but unfortunately, prices are set to move up as crude oil prices rise, according to a recent Lundberg Survey.

According to the recently published report, which surveys almost 7,000 gas stations, the national average for self-serve, regular unleaded gas reached $2.7932 a gallon as of Sept. 21, down from $2.8135 a gallon on Sept. 7.

“That’s a very small slip in the U.S. average price. It came from a substantial down correction in the Midwest, where gasoline supplies had been very tight but are normalizing,” survey editor Trilby Lundberg told the Associated Press. Lundberg added that prices are up about 37 cents per gallon from a year ago–39 cents per gallon below the all-time U.S. average high of $3.1827 on May 18.

“The two-cent drop is only an interruption in the upward march for retail gasoline,” she added. “There’s now well more than a dime waiting in the wings” due to a rise in crude oil prices.”