U.S. gasoline prices fell to the lowest level in three weeks due to lower crude oil costs, the Energy Department said Tuesday.

The national price for regular unleaded gasoline dropped 3.1 cents over the last week to $2.73 a gallon, the department’s Energy Information Administration said in its weekly survey of service stations.

While drivers are still paying 11 cents more a gallon than a year ago, the pump price is down sharply from the record $4.11 reached two years ago.

Gasoline prices are expected to average less than $3 a gallon for the rest of this summer, barring a major disruption in petroleum supplies such as a hurricane, according to the EIA.

The fall in motor fuel prices mirrored a decline last week in crude oil costs, which fell $6 a barrel, and accounts for more than half of a refiner’s cost for making gasoline.

In its weekly price survey, the EIA found the West Coast had the most expensive gasoline at $3.05 a gallon, down half a penny. By city, San Francisco had the highest price at $3.16, down 1.3 cents.

The Gulf Coast states had the lowest regional price at $2.58 a gallon, down 3.3 cents. Houston had the cheapest city pump price at $2.52, down 1.7 cents.

The agency also said gasoline prices were up 0.7 cent at $2.97 in Seattle; down 6.2 cents at $2.86 in Chicago; down 2.4 cents at $2.79 in Miami; down 1.6 cents at $2.77 in New York; down 0.9 cent at $2.68 in Boston; down 10 cents at $2.67 in Cleveland and down 1.1 cents at $2.65 in Denver.

Separately, the average price for diesel fuel dropped 3.2 cents to $2.92 a gallon, up 33 cents from a year ago, the EIA said.

The West Coast had the most expensive diesel at $3.08, down 2.2 cents. The Gulf Coast region had the cheapest diesel fuel at $2.87, down 2.7 cents.