WASHINGTON (AP) — A new report says states can receive more than $9 in federal money for every dollar they spend to cover low-income residents under President Barack Obama's health care law.

Expanding Medicaid to cover about 20 million more low-income people will cost a total of more than $1 trillion from 2013 to 2022, the report estimates. But states will pay just $76 billion of that, or roughly 7 percent of the cost.

Two nonpartisan groups, the Kaiser Family Foundation and the Urban Institute, collaborated on the new analysis.

It also found that a few states might actually spend less than they do now.

The Supreme Court allowed states to opt out of the health care law's Medicaid expansion, an issue that will be hotly debated when state legislatures meet next year.