PORTLAND, Maine (AP) Maine has one of the highest rates of coronavirus vaccination in the country, but some of the rural counties in the state lag behind the more populated areas.

More than 52% of Maine’s population has received a final dose of the vaccine. Like other New England states, Maine has paced the nation in getting the shots to residents.

The pace in Maine has been buoyed by a 63% mark in Cumberland County, which is the most populated county in the state and the location of its largest city, Portland. Several rural counties, however, are still below 50%, according to data from the office of Gov. Janet Mills, a Democrat.

Somerset County has the lowest rate in the state at about 41%, the governor’s office reported. Ten of Maine’s 16 counties are below 50%. Those counties include Washington, Franklin and Piscataquis, the three least populated counties in the state.

Public health officials in Maine have used a mobile vaccine unit to help get the vaccine to rural areas. The unit is set to provide vaccines in Calais, in Washington County, through Thursday at the Thomas Dicenzo Athletic Complex.

“Drop-in vaccinations are also available at this location,” the governor’s office said on its website.