RICHMOND, Va. (AP) _ Federal officials say the cost of a benchmark plan on the health care exchange will go up 4 percent for Virginia residents. The increase for 2016 coverage in Virginia is lower than the average for the 37 states that are using the Healthcare.gov website. The U.S. Department of Health and Human Services says premiums for the benchmark plan across all states relying on the federal exchange will go up an average of 7.5 percent. The benchmark plan is the second lowest-cost silver plan. Some states are seeing double digit increases, while rates are decreasing in a handful of states. The third open enrollment session begins on Nov. 1. At the end of the 2015 enrollment period, more than 385,000 Virginians had selected a plan on the exchange.