Ongoing preparation for the processing of a summer blend of gasoline is behind the steady increase in retail gasoline prices, analysis finds.

Motor club AAA reports a national average retail price for a gallon of regular unleaded gasoline at $2.04 for Tuesday, a slight increase from the previous day and nearly 3 percent, or about 6 cents, higher than one week ago.

Last week, the national average price moved to more than $2 for the first time this year as refiners started to conduct the routine maintenance necessary to switch to processing a summer blend of gasoline. That's resulted in less gasoline supplies, moving prices higher. During the spring, demand also increases as more drivers look to break cabin fever by hitting the road.

"The combination of the above factors generally contributes to rising prices at the pump, leading into the busy summer driving season," the motor club said in a weekly retail market report.

Crude oil prices, which account for the bulk of the price consumers pay for gasoline, have been relatively stable, holding near the $40 mark for most of March. Markets have seesawed on talks of a potential meeting in April between the Organization of Petroleum Exporting Countries and other major producers on holding output steady at January levels to stabilize the market. AAA said in its report that most market analysts are skeptical about the outcome of the deal.

"As crude oil prices fell gently last week back under $40 per barrel, motorists shouldn't necessarily expect the worst increases to be over just yet," Patrick DeHaan, a senior analyst with consumer price watchdog GasBuddy, said in a separate emailed statement. "Until the bulk of refinery maintenance season wraps up in late May, we likely won't see the lower oil prices immediately bring relief to the pump as oil and gasoline inventories continue to move in the opposite direction."

The price for Brent crude oil, the global benchmark, was around $39.57 per barrel early Tuesday.

New Jersey has the lowest state average price in the nation at $1.84 per gallon. The national average price, meanwhile, is 15 percent, or 38 cents, less than this date in 2015.