UNITED STATES -- Gas prices make a slow but steady decline. The latest Lundberg survey shows the average price for a gallon of gas has dropped five cents over the past two weeks. The survey found the current national average is $3.91 per gallon. This is the first time the Lundberg survey has shown a decline in gas prices this year.

AAA's numbers have shown several declines, but the auto club tracks data differently and more often than the Lundberg survey.

Analysts say crude oil prices have been stable, allowing gas prices to come down. The gas supply is up, so the downward trend should continue as long as crude oil doesn't fluctuate.