Midwestern region sees largest uptick in prices based on production issues.

The national average price for regular unleaded gasoline hit $2.74 on Memorial Day, marking the highest pump price of the year, but the lowest pump price for the Memorial Day holiday since 2010, AAA reported.

Drivers are paying three cents more than one week ago, eight cents more than two-weeks ago and 21 cents more than one month ago to fill up at the pump.

AAA pointed out that pump prices are trending higher because of an increase in the price of global crude and localized refinery issues, particularly in the Midwest and on the West Coast. The Midwest has seen the most dramatic weekly increase, which was attributed to production issues in the market. ExxonMobil’s Joliet, Ill. refinery is operating at reduced production levels, and CITGO’s refinery in Lemont, Ill. is scheduled to conduct maintenance in the coming days. Illinois (+13 cents) and Ohio (+10 cents), for example saw double digit increases.

California ($3.76), Nevada ($3.32) and Hawaii ($3.28) continue to post the highest gas prices in the country, while South Carolina ($2.43), Mississippi ($2.44) and Oklahoma ($2.45) are paying the lowest prices at the pump.