Health Insurance

16.4M gain health coverage under Obamacare: Government

Obamacare has led to the biggest decrease in the numbers of Americans lacking health insurance in four decades—with minorities and young adults seeing the largest gains in coverage, the federal government said Monday.

A total of 16.4 million previously uninsured adults nationwide obtained health coverage since the Affordable Care Act became law, according to the U.S. Department of Health and Human Services.

Read MoreObamacare's new 'special' sign-up period for tardy

And the uninsured rate among adults dropped from 20.3 percent in October 2013 to 13.2 percent by March 4 of this year—the time during which Obamacare marketplaces have been selling health plans, HHS said.

Terry Donald, a beneficiary of the Affordable Care Act, is flanked by Sen. Chris Murphy, Democrat of Connecticut, and Sen. Al Franken, Democrat of Minnesota, during a news conference to discuss the Affordable Care Act case being heard at the Supreme Court on March 4, 2015, in Washington, D.C.
Getty Images

That is a 35 percent reduction in the rate of people without health coverage. As of this month, there were about 26 million American adults without health insurance, compared to about 40 million without coverage just before the Obamacare insurance marketplaces launched in the fall of 2013.

HHS credited the large decrease in the overall uninsured rate to Obamacare's creation of those government-run marketplaces that sell health insurance, the loosening of Medicaid eligibility requirements in more than half of the country and to the Affordable Care Act provision that allows young adults to stay on their parents' health plans until they turn 26. The provision related to young adults began in 2010.

"This is an historic drop in the uninsured, and nothing since the adoption of Medicare and Medicaid even comes close," said Dr. Richard Frank, HHS's assistant secretary for planning and evaluation, during a call with reporters.

HHS Secretary Sylvia Burwell said, "When it comes to the metrics of affordability, access and quality, the evidence shows that the Affordable Care Act is working, and families, businesses and taxpayers are better off as a result."

The plunge in the overall uninsured rate was matched by drops across all major races and ethnic groups, officials said. However, minorities saw the largest decreases in their uninsured rates.

Read MoreFewer people lost health plans due to Obamacare

Latinos had a 12.3 percentage point reduction in their uninsured rate, and the uninsured rate for African-Americans fell by 9.2 percentage points, HHS said. Whites saw a 5.3 percentage point reduction in their uninsured rate.

In terms of sheer number, 6.6 million white adults gained coverage, 2.3 million African-American adults added coverage and another 4.3 million Latino were newly insured, according to HHS. After those gains, just 9 percent of white adults lack health coverage, and 13.2 percent of African-American adults remain uninsured.

But Latinos, by far, retained their status as the leader among the uninsured—29.5 percent of Latino adults still lack health coverage.

Among young adults between the ages of 19 to 25, the uninsured rate dropped from 34.1 percent to 26.7 percent since 2010, the year in which the ACA was signed into law.

The decline in the overall uninsured rates "was especially strong" in states that have expanded the eligibility standards for the Medicaid programs that they jointly run with the federal government, according to HHS. The ACA originally mandated that states expand their Medicaid programs to cover nearly all people who earn less than 138 percent of the federal poverty level—$16,242 in most of the U.S.—but a 2012 Supreme Court ruling left the decision to expand up to individual states.

Currently, 28 states and the District of Columbia have expanded their Medicaid programs. Another 22 states kept their stricter restrictions on Medicaid eligibility.

In so-called nonexpansion states, the overall percentage of people without any health insurance was 23.4 percent as of October 2013. Since then, the uninsured rate in nonexpansion states has decreased by 6.9 percentage points, according to HHS.

Read MoreEven the insured struggle to pay medical bills

And in those states, the uninsured rate among people who earn less than 138 percent of poverty level fell by 7 percentage points.

But in so-called expansion states, there was a 7.4 percentage point drop in the overall uninsured rate. And there was a 13 percentage point drop in the uninsured rate among the poor, or nearly twice the drop seen in nonexpansion states among that same group of people.

HHS did not release a state-by-state breakdown of the uninsured rate.