AUGUSTA — A Maine survey indicates the state’s average heating oil price has risen to $3.50, an increase of 6 cents over the past week.

Director Ken Fletcher of the Governor’s Office of Energy Independence and Security said Monday that domestic inventories are at reasonable levels, but that “markets remain uncertain.” The survey indicated actual prices ranged from $3.30 in southern Maine to $3.70 in central and northern regions.

The U.S. Department of Energy says projects that heating oil and propane prices will increase 10 percent over last year, with the households that use heating oil spending an extra $193 on average.