An estimated 1.5 million, or 13 percent, of people dropped off health-insurance coverage rolls this year because they failed to pay for the policies they selected on Affordable Care Act marketplaces, the White House said Tuesday. The Obama administration announced 10.2 million people were enrolled as of March 31, down from the 11.7 million who signed up for coverage through federal and state marketplaces earlier this year. About 85 percent of enrolled people received subsidies to help them afford the coverage. Sylvia Mathews Burwell, the secretary of Health and Human Services, said nearly 6.4 million people in 34 states are receiving government subsidies to help afford the insurance on the federal exchange. However, those people are at risk of losing the subsidies should the Supreme Court rule that tax credits only apply to states where exchanges have been established.