Gas prices fell about 2 cents in the past two weeks, reflecting recent drops in the price of crude oil and plentiful supply, the Lundberg Survey (search) said Sunday.

The combined national average for all grades of gasoline was $1.89, said Trilby Lundberg (search), who publishes the semimonthly Lundberg Survey. The price was down from $1.91 on Aug. 27.

The survey, taken Friday, polled about 6,000 gas stations across the United States.

Self-serve regular, the biggest seller, was $1.86. Mid-grade national average was $1.96 and the U.S. average of premium was $2.05.

Lundberg noted that crude oil prices, which began the month at around $44 per barrel, have been declining on most trading days since then. Prices at the pump are beginning to catch up with those drops, she said.

Retail prices declined despite the Labor Day weekend (search). Lundberg said the idea of significantly increased demand on what are considered to be heavy driving holidays is a "myth." Pump prices are more closely tied to crude oil prices and seasonal changes in driving and supply, she said.

Prices have dropped about 22 cents since reaching a peak of $2.10 for the national average of all grades on May 21.