NEW YORK (MarketWatch) — It hasn’t been this cheap to fill up your tank for 5½ years.

The national average price of gas has declined for 88 days in a row – the longest streak on record, according to AAA’s Fuel Gauge Report. If that’s not enough good news, the decline, which began on Sept. 25, has accelerated over the past week and doesn’t show signs of slowing.

The week-over-week drop of 15 cents was the largest decline in more than six years. Motorists are paying 43 cents less than a month ago and 85 cents less than a year ago, according to AAA. Prices now sit at an average $2.39, the lowest average price per gallon since May 2009.

On Sunday, prices broke the previous record of 86 days, set in 2008 during the height of the Great Recession, with prices discounting in every state and Washington, D.C. on a week-over-week, month-over-month and year-over-year basis.

In fact, it now costs under $3 a gallon to fill up your tank everywhere in the U.S. except Hawaii and Alaska. Gas is cheapest in Missouri, Oklahoma, Texas and Kansas.

And the decline also doesn’t show signs of slowing — at least through the New Year. Barring any disruptions in domestic production or unexpected spikes in oil prices, AAA predicts prices could drop another 10 to 15 cents per gallon before the end of 2014.

AAA says cheaper gas is saving Americans an estimated $450 million a day.

The streak was sparked by declining crude prices, which have fallen by more than $50 a barrel since June, as well as ample gas supply.

Oil has tumbled more rapidly over the past few weeks, with light sweet crude oil futures (WTI) closing down $2.14 per barrel at $57.81 on the NYMEX on Friday, the lowest settlement since May 2009.