U.S. annual inflation reached 3.7% in September, a four-month high, as gasoline prices rose sharply, federal data released Wednesday showed. The reading was slightly above economists’ expectations and up from 3.4% in August.

Gasoline prices jumped more than 9% from August and accounted for over half of September’s overall price increase, the Bureau of Labor Statistics said. Shelter costs also rose, while food prices were unchanged from the previous month. Food inflation stood at 2.5% over the year.

The September reading was also above February’s 2.4% rate, recorded before the Iran war. Conflict in the region has pushed up fuel costs, though inflation eased somewhat over the summer during an intermittent pause in fighting. AAA figures put the national average gasoline price above $4.30 a gallon, compared with less than $3 before the war.