Retail gasoline prices in the United States remain at historic lows, though regional intercontinental dynamics make for a fluid situation, AAA reported.

The U.S. national average retail price for a gallon of regular unleaded gasoline at $2.12 is the lowest it's been in more than 100 days and the lowest for this date in more than a decade. The national average price has dropped for 51 of the past 52 days and is on average 3 cents less than this time last week.

In a weekly retail market report, AAA said low crude oil prices and low consumer demand are putting negative pressure on prices at the pump.

"While a record number of American motorists have hit the road for summer travel, sharply lower gas prices have not triggered the sharply higher gasoline demand that many analysts had anticipated," the report read.

At the regional issue, California, which was plagued last year by chronic refinery outages, is the only state in the nation with a retail gasoline price that's more than a dollar lower than last year. Alaska and Nevada are close behind with discounts of 86 cents and 77 cents, respectively. The lack of regional refinery issues in that market, AAA said, is in part behind the steady move lower for the national average.

The story is different in the Great Lakes region, where Michigan had the largest overnight spike last week at 3 cents, while Indiana had the largest weekly increase at 10 cents per gallon. Two refineries in Illinois and two in Ohio had unplanned outages, causing dramatic volatility in the Great Lakes states.

Nevertheless, regional supplies to refineries remain strong and AAA reports more than 40 percent of all retail gasoline stations in the country are posting prices below the $2 mark.

"With gasoline supplies high and oil prices low, pump prices are likely to remain relatively cheap through the remainder of the summer and into the fall," the report read.