Pump prices are still expected to remain lower than years past as seasonal maintenance gets underway at refineries.

The national average price of gas moved 12 cents per gallon higher this past week, ending March 14. The price jump marks the largest weekly increase since March 2015.

AAA pointed to a decline in gasoline supplies, relatively strong demand and continued refinery maintenance as the reason behind the double-digit uptick.

The national average price of gas as of March 14 now stands at $1.94 per gallon. Despite the increases, gas consumers are still saving 50 cents per gallon at the pump compared to this same date last year, AAA pointed out.

It is normal for prices to climb in spring as demand increases and refineries conduct seasonal maintenance. Thanks to lower-than-expected prices of crude oil and plentiful supplies, pump prices are expected to stay relatively low in comparison to the gas prices of recent years.

California ($2.59) overtook Hawaii this week, regaining its spot as the nation’s most expensive market for retail gasoline. Meanwhile in Hawaii ($2.54) drives are paying five cents more than they were last week for fuel. New Jersey ($1.69) and South Carolina ($1.70) are currently the nation’s least expensive markets for gasoline.

Only six states are currently posting prices at or below $1.75, compared to 20 last week.