A number of factors are causing fuel prices to fluctuate.

Despite the switch from summer to winter blend gasoline and the surplus of crude oil supplies, fuel prices have increased slightly over last week.

According to AAA, as of Mon., Oct. 3, 2016, the national average price for gasoline was $2.22 per gallon, two cents more than one week prior and one cent more than a month ago. However, despite the increase in fuel prices, drivers are still saving approximately seven cents per gallon over this time last year.

While the national average has increased slightly, drivers in 21 states are paying less at the pump this week. Additionally, AAA reported that fuel prices have been relatively steady over the past month, but some regions have experienced drastic price changes over the past four weeks, mainly due to the disruptions on the Colonial Pipeline and refinery maintenance.

Last week, gas prices spiked in the Midwest because of both scheduled and unscheduled maintenance at BP’s Whiting refinery, which impacted the region’s supply, AAA reported. Pump prices may see prices fluctuate over the next few weeks following the OPEC production agreement, and as a result of continued refinery maintenance and a possible hurricane along the East Coast.

According to AAA, only three states are reporting average gas prices below $2 per gallon, including New Jersey ($1.98), Texas ($1.98) and Missouri ($1.99).