"For some time, retailers had not been passing along all of the wholesale costs to the customer at the pump," said Trilby Lundberg, who publishes the Lundberg Survey.

Gasoline prices have dropped about 15 cents the last two weeks, to a national average of $2.78 for unleaded fuel, according to the Lundberg Survey.

The Lundberg Survey of 10,000 service stations nationwide said the average price for all grades of gasoline had fallen nearly 2 cents in the last two weeks, to $1.07 a gallon.

Italy still uses a great deal of regular leaded gasoline, costing about $3.70 a gallon, according to the Lundberg Survey, which monitors international gasoline prices.

The average price of gasoline was 94.9 cents a gallon, according to the Lundberg Survey of gasoline prices at 12,500 stations across the United States.

LEAD: The national average price of gasoline has fallen 1.67 cents a gallon since early June, the Lundberg Survey reported.

The average price for all grades, including taxes, was $1.37 a gallon Friday, according to the Lundberg Survey of 10,000 gasoline stations nationwide.

In its most recent check of 12,000 service stations, on Nov. 18, the Lundberg Survey found the nation's average price of unleaded regular gasoline was 90.6 cents.

The Lundberg Survey of 12,000 gas stations nationwide showed that the average retail price of gasoline was 99.61 cents last Friday, the industry analyst Trilby Lundberg said.

The average national price for a gallon of gas, including all taxes, was 117.72 cents, according to the biweekly Lundberg Survey of nearly 13,000 service stations, completed Friday.