(CNN) -- Gas prices fell four cents over the last two weeks, to a national average of $2.75 for a gallon of self-serve regular, according to a survey published Sunday.
The bad news: that price is still 47 cents higher than it was a year ago, the Lundberg Survey found. And according to publisher Trilby Lundberg, the recent modest price slide "is not a trend for the future."
Recent increases in wholesale prices for crude oil are expected to spell higher gasoline prices. And gasoline supply is tightening, as refineries shut down some capacity to make seasonal changes aimed at ensuring they'll have enough heating oil in the winter months ahead, Trilby Lundberg said.
While overall prices dropped in the two weeks preceding the survey of thousands of gasoline stations on Friday, the drop was not even across the country. East Coast prices showed virtually no change on average, while in the West, prices on average went up, Lundberg said.
The lowest average price of a gallon of self-serve regular was in Newark, N.J., at $2.52, the survey found. The highest was in Honolulu, at $3.09. 
