A new study estimates that more than 10 million adults gained health insurance by midyear as the coverage expansion under President Barack Obama's law took hold in much of the country.
The study published Wednesday in the New England Journal of Medicine found that the share of Americans ages 18 to 64 without insurance dropped by a little more than 5 percentage points.
States that embraced the law's Medicaid expansion saw significant coverage gains among low-income uninsured people. About half the states have expanded.
The law offers subsidized private insurance for middle-class people who don't have access through their jobs and expanded Medicaid for low-income adults.
The latest study results are in line with findings by Gallup and with estimates from the Congressional Budget Office.