WASHINGTON, D.C. — Labor Day holiday gasoline prices hit their lowest level in more than a decade this month.

According to Washington, D.C.-based AAA, the national retail average price fell to $2.40 per gallon on Labor Day, or $1.04 per gallon below this same time last year. As of Sept. 8, the average had fallen 22 consecutive days to rest at $2.39 per gallon, amassing a 28-cent-per-gallon (CPG) decline along the way.

At $2.39 per gallon, the national average was 7 CPG lower than a week ago, and 20 CPG vs. a month ago, AAA reported. Year over year, the national average was $1.05 per gallon lower.

U.S. drivers saw gas prices this summer driving season—Memorial Day to Labor Day—an average of 89 CPG lower than last year.

More To Come

AAA expects prices to keep falling into autumn as demand hits a seasonal decline, assuming that crude prices stay low and routine refinery maintenance runs smoothly. According to the U.S Energy Information Administration, refineries were experiencing above-average utilization rates, and had more maintenance planned for 2015 vs. previous years. While this might slow gas prices’ expected decline this autumn, it should not stop or reverse it, says AAA.

A seasonal switch to less-expensive winter-blend gasoline in parts of the United States beginning Sept. 16 should also weight down the price average.

South Carolina enjoyed the lowest state average for retail gasoline prices at $1.97 per gallon on Sept. 8. The highest averages hit Alaska ($3.35 per gallon), California ($3.26), Nevada ($3.10), Hawaii ($3.03) and Washington ($2.88), according to AAA.

State retail averages fell in almost every state on a week-over-week basis, with 26 states seeing a 5-CPG or greater savings. Five states—four of which were hit by a recent refinery outage—enjoyed double-digit declines. They include Indiana, where prices fell 17 CPG week-over-week, as well as Ohio (-15 CPG), Illinois (-14 CPG) and Michigan (-12 CPG). Delaware and Utah were the only two states to see increases, up 4 CPG and a fraction of a penny week-over-week, respectively.

On a month-over-month basis, the average retail price for gasoline fell by 10 CPG or more in 43 states and Washington, D.C., according to AAA. Eight states enjoyed a 25-CPG or greater savings, led by California (-33 CPG), Oregon (-29 CPG) and New Jersey (-27 CPG).

And on a year-over-year basis, average retail gasoline prices were down at least 75 CPG in 47 states and Washington, D.C. The three states that did not see that big of a decline: Alaska (-67 CPG), California (-56 CPG) and Nevada (-59 CPG). In 33 states, gas prices were off $1 or more per gallon, with Indiana (-$1.28), Michigan (-$1.26) and Ohio (-$1.26) seeing the biggest declines year over year.

Below $2 Per Gallon?

According to data from GasBuddy, Gaithersburg, Md., the national retail average dropped almost 7 CPG over the last week to hit $2.391 per gallon the morning of Sept. 8. Patrick DeHaan, senior petroleum analyst at GasBuddy, said motorists should be enjoying $1.99 or lower prices by the end of the year.

“Better than one in 10 stations in the country now offer gasoline prices at $1.99 per gallon or less, and gas prices in 48 of the nation’s 50 states fell in the run-up to the [Labor Day] holiday itself, showing that holidays aren’t always a catalyst for price increases,” said DeHaan. “As we begin to near the terminus for summer gasoline, I expect prices to continue moving lower, with our projections aiming at a sub-$2-per-gallon average by Christmas or perhaps even earlier.”