The number of counties at risk of having no insurer on their Affordable Care Act (ACA) exchange has fallen to just two, with Centene stepping in to cover potentially bare counties in Nevada.

Bare counties have been steadily filled in on maps of ACA participation since CMS reported in late July that 40 counties were projected to have no marketplace insurer next year. Most were in Nevada, where 14 mostly rural counties didn’t have an insurer. Centene has now stepped in to cover those areas, according to the Nevada Independent, under its SilverSummit plan.

Centene had already been set to cover one bare county when it announced it would sell coverage under its Ambetter brand in 49 Indiana counties next year, up from 32 in 2017, including Wayne County, which had 1,166 enrollees at risk of having no marketplace insurer.

Its move into Nevada leaves just two counties—Paulding County, Ohio and Menominee County, Wisconsin—at risk of having no insurer on its ACA exchange. Combined, only 381 residents had enrolled in marketplace coverage in those areas in 2017.

Overall, however, enrollees will have fewer choices in 2018, with Bloomberg reporting 23 percent of enrollees will have only one insurer to choose from on the exchanges. Eight states—Alabama, Alaska, Iowa, Mississippi, Nebraska, Oklahoma, South Carolina and Wyoming—could be limited to a single marketplace insurer statewide.

Some of those single-insurer areas were served by Anthem, which has been scaling back its ACA offerings in many parts of the country, including Georgia, Indiana, Nevada, Ohio and Wisconsin. On Aug. 11, the insurer announced it wouldn’t participate in Virginia’s marketplace for 2018.

“Today, planning and pricing for ACA-compliant health plans has become increasingly difficult due to a shrinking and deteriorating Individual market, as well as continual changes and uncertainty in federal operations, rules and guidance, including cost sharing reduction subsidies and the restoration of taxes on fully insured coverage,” Anthem said in a statement. “As a result, the continued uncertainty makes it difficult for us to offer Individual health plans statewide in Virginia.”

The insurer will maintain off-exchange individual policies in Washington and Scott Counties and the city of Bristol.