The average premium for a benchmark plan at HealthCare.gov will decline 1.5 percent in 2019 to $406, the Centers for Medicare & Medicaid Services announced today. For the 39 states using HealthCare.gov to sell plans in the individual health insurance market, the average premium change in 2019 for a benchmark (second-lowest-cost silver) plan for a 27-year-old single non-smoker will range from a 26.2 percent decline in Tennessee to a 20.2 percent increase in North Dakota, according to data released by the agency. An additional 23 qualified health plan issuers will offer medical coverage through the federally-facilitated exchange in 2019, and 29 issuers will expand their coverage area. As a result, the number of counties with only one insurer on the exchange will drop from 56 percent to 39 percent, CMS said. Open enrollment in 2019 through HealthCare.gov and most state exchanges begins Nov. 1 and runs through Dec. 15.