The national average for gasoline prices declined for 21 consecutive days, buoyed by the increase in crude oil production in the United States and lower driving demand, according to retail analysis.

The national average for regular unleaded gas is $2.27 a gallon, which is 4 cents lower than one week ago and 5 cents less than a month ago, according to motor club AAA. GasBuddy also reported the average price at $2.27, down 2.8 cents from last week and 6.2 cents from the previous month.

Compared with one year ago, prices are 47 cents more per gallon, according to both sources.

The top four highest prices nationally remain on the West Coast, including in Hawaii ($3.07), California ($2.80), Alaska ($2.74) and Washington ($2.73), according to AAA.

AAA reports prices have remained stable in the West despite increased gasoline production and supply in California.

In the Northeast, gas prices were the highest in Pennsylvania at $2.57 (5th) and New York at $2.50 (8th).

In the central part of the country prices remain "flat," according to AAA, despite the shutdown of a pipeline owned by Magellan Midstream Partners last Wednesday after a section of the pipeline was leaking diesel fuel in Iowa. The biggest decline was in Ohio with an 11-cent decline in one week and 33 cents from a month ago. Michigan and Illinois each dropped 9 cents from last week.

Prices remain the lowest on the Gulf Coast, where most of the oil refiners are located in the United States. AAA said the lowest prices in the nation are in South and Southeast -- South Carolina ($2.04), Alabama ($2.07), Mississippi ($2.08), Texas ($2.10) and Arkansas ($2.11).

Baker Hughes reported that drillers added 15 rigs in the United States. The oil rig count stands at 556, the highest since November 2015. This compares with Organization of Petroleum Exporting Countries efforts to rebalance the global oil market.

Brent crude oil was up 51 cents a barrel at $55.74 before markets opened Tuesday in New York. U.S. light crude gained 57 cents to $53.20.

One year ago Brent crude was trading 1.78 percentage points lower and its 52-week high was $58.53 but the low was $38.04. For light crude, its 52-week high was $56.24 and the low was $38.10.

"End-of-month surveys of OPEC production cuts are expected tomorrow and traders will be paying close attention to the cartel's agreement compliance," AAA noted. "Market watchers will also keep a close eye on U.S. production and the impact it has on supply and demand."