The average price of a gallon of gas has fallen below $2 in nearly a quarter of the country's states, according to AAA.
The national average currently stands at $2.19 for a gallon of regular gas, the lowest it's been since early December 2016. That's down 13 cents from a week ago and 36 cents lower than a year ago.
Oklahoma is the cheapest, with a cost per gallon of regular going for $1.84. Hawaii and California are the two most expensive states for a gallon of regular, at $3.52 and $3.28 respectively.
"This is unprecedented," Tom Kloza, head of energy analysis for the Oil Price Information Service, told CNN Business.
Kloza expects that the national average will soon drop between $1.99 per gallon with some states hitting $1 per gallon or less.
The national average price will probably decline further ‐perhaps to between $1.25 to $1.50 per gallon — in the next few months, he said.