CAMARILLO, Calif. â€"  The average U.S. price of a gallon of gasoline has dropped seven cents over the past two weeks, but prices in Chicago still lead the nation according to one national survey.

The Lundberg Survey of fuel prices, released today, puts the price of a gallon of regular at $3.85.

Midgrade costs an average of $4.00 a gallon, and premium is at $4.12.

Diesel dropped three cents to $4.15 a gallon.

Of the cities surveyed, Chicago has the highest at $4.32. Tulsa, Okla., has the nation's lowest average price for gas at $3.40.

In California, the lowest average price was $4.07 in Fresno. The highest was $4.21 in San Francisco. The average statewide for a gallon of regular was $4.16, down about half a cent.