The national average for gas prices dropped to $2.18, which 48 cents cheaper than mid-September last year, and is being driven by low oil prices.

The latest Energy Information Administration (EIA) report measures oil demand at 8.48 million barrels per day, which is a slight uptick from the previous week’s 8.39 million barrels per day, AAA said. However, the small increase, which was likely due to holiday road trips, is still 461,000 barrels per day lower than last year at this time.

On the week, all states saw gas prices decrease or remain stable at the pump, according to AAA. With the nation entering the fall driving season, which typically sees fewer road trips, a continued drop in demand will likely lead to pump prices continuing to decrease.

The nation’s top 10 largest weekly decreases were Delaware (down 5 cents), Florida (down 4 cents), Maryland (down 3 cents), West Virginia (down 3 cents), Utah (down 3 cents), Colorado (down 2 cents), South Carolina (down 2 cents), Georgia (down 2 cents), New Jersey (down 2 cents) and North Carolina (down 2 cents).

Meanwhile, the nation’s least expensive markets are Mississippi ($1.84), Texas ($1.85), Arkansas ($1.87), Oklahoma ($1.88), Missouri ($1.88), Louisiana ($1.88), South Carolina ($1.90), Alabama ($1.90), Tennessee ($1.93) and Kentucky ($1.96).