While the Affordable Care Act has reduced the percentage of uninsured people in the United States from 16 percent to 9 percent, more can be done within its framework to achieve universal coverage, an analysis by the Brookings Institution argues. Published in the New England Journal of Medicine, the policy brief, Building on the ACA to Achieve Universal Coverage, outlines four basic steps toward that goal: implementing Medicaid expansion in every state; increasing and expanding financial assistance to people who purchase coverage through the health insurance marketplace; ensuring that people actually enroll in the affordable coverage for which they are eligible; and extending coverage to undocumented immigrants. According to the analysis, increasing Medicaid expansion states' base federal matching rate for Medicaid spending by about 2 percentage points (or reducing the rate by the same amount for states that refuse to expand Medicaid coverage) would make expansion effectively free for a typical state, while making marketplace coverage affordable would entail increased tax credits to offset insurance premiums, higher cost-sharing subsidies to offset out-of-pocket costs, and extension of subsidies to people with incomes above 400 percent of the federal poverty level. Those without coverage who are ineligible for Medicaid or CHIP would be automatically enrolled in a "backstop" insurance plan, which could be either public or private. The costs of these reforms could be covered by measures similar to those that paid for the ACA, the report notes, which included reforms to Medicare payments and revenue increases.