WASHINGTON -- A major new survey finds that a growing percentage of Americans gained health insurance as the initial sign-up season for President Barack Obama's health care law drew to a close last month.
Released Monday, the Gallup-Healthways Well-Being Index measured the share of adults without health insurance. That shrank from 17.1 percent at the end of last year to 15.6 percent for the first three months of 2014.
The decline of 1.5 percentage points would translate roughly to more than 3.5 million people gaining coverage. The trend accelerated as the March 31 enrollment deadline loomed.
"The Affordable Care Act, commonly referred to as 'Obamacare,' appears to be accomplishing its goal of increasing the percentage of Americans with health insurance," said Gallup's analysis of the findings.
The survey is important because it combines the quick turnaround of media polls with extensive outreach usually seen in government research. Gallup interviewed more than 43,500 adults, or more than 40 times the number in a typical national media poll.
Coming a week after the close of the health care law's first enrollment season, Gallup's numbers suggest a more modest impact on coverage than statistics cited by the Obama administration.
The administration says 7.1 million have signed up for subsidized private plans through new insurance markets, while 3 million previously uninsured people gained coverage through the law's Medicaid expansion. Millions more remain potentially eligible for marketplace coverage under various extensions the administration has issued.
However, those numbers are not comparable with Gallup's.
The White House figure of 7.1 million insurance exchange sign-ups includes insured people who switched their previous coverage, as well as people who have not paid their first month's premium, and who would therefore still be uninsured.
Also, Gallup is counting just adults, while the administration figures include children as well.
It may take much of the rest of the year to get a true bottom line of the health care law's impact on coverage.
But Gallup's numbers do show an improving trend. The share of Americans without coverage is at its lowest since late 2008, before Obama took office, the survey found.
That's independent validation for the White House, and it also helps calm concerns about the fallout from last fall's wave of insurance cancellations.
Some feared the cancellations of more than 4.7 million policies that didn't measure up to the law's standards would actually swell the ranks of uninsured people. That created huge political problems for Obama, who had promised Americans they could keep their insurance if they liked it.
About half the states authorized extensions belatedly granted by the White House.
Gallup found the biggest insurance gains were among lower-income people and among African-Americans.
Among people with household incomes of less than $36,000 a year, the share of uninsured shrank by 3.2 percentage points from levels at the end of 2013.
African-Americans saw their uninsured rate drop by 3.3 percentage points.
Although the proportion of Hispanics without coverage fell by 1.7 percentage points, Latinos remained more likely than any racial or ethnic group to lack access, with 37 percent uninsured.
Gallup found gains in coverage among all age groups, but not much evidence of a late surge of younger people that the administration had hoped for to help keep premiums in check.
Results were based on telephone interviews conducted Jan. 2 -March 31 with a random sample of 43,562 adults 18 and older living in all 50 states and Washington, D.C. For results based on the total sample of national adults, the margin of sampling error is plus or minus 1 percentage point at the 95 percent confidence level.