U.S. gasoline (search) costs declined for the fifth week in a row, with the national pump price falling 1.6 cents from last week to an average $1.921 a gallon, the government said on Monday.

However, the latest price for regular unleaded gas is still up 43 cents from a year ago, according to the U.S. Energy Information Administration's (search) weekly survey of service stations.

The Energy Department's analytical arm said it expects retail gasoline prices to continue falling in the coming weeks.

Motor fuel prices are dropping as Saudi Arabia (search) and other OPEC members put more crude oil on the market to meet global petroleum demand. Crude accounts for almost half the cost of making gasoline.

Oil for delivery in August settled $1.31 lower at $36.24 a barrel on Monday at the New York Mercantile Exchange.

The EIA's weekly report also showed the retail price for cleaner-burning reformulated gasoline, sold in polluted metropolitan areas, declined 2.3 cents to $2.049 a gallon.

The West Coast had the most expensive regular unleaded gasoline, with the price down 2.5 cents to $2.175 a gallon. San Francisco topped the agency's city survey of gasoline costs, as the price fell 1.6 cents to $2.27 a gallon.

The U.S. Gulf Coast had the cheapest fuel by region, with the price down 2.9 cents at $1.809 per gallon. Houston had the lowest pump price at $1.778 a gallon, down 3.1 cents.

The weekly report also showed gasoline prices were down 5.2 cents to $2.109 in Seattle, down 1.9 cents to $2.01 in Miami, down 2.3 cents to $2.075 in New York City, down 1.5 cents to $1.936 in Chicago, and up 4.4 cents to $1.783 in Cleveland.

Separately, the EIA survey said the average pump price for diesel fuel was unchanged at $1.70 a gallon, but was up 28 cents from a year earlier.

Truckers on the West Coast paid the most for diesel fuel at $1.969 a gallon, up a penny from the prior week. The Gulf Coast states had the cheapest diesel at $1.624, up a slight 0.1 cent.