America's uninsured rate plummeted last year, with the improvement driven by states that have fully implemented the Affordable Care Act, a new nationwide Gallup survey indicates.
Led by Arkansas and Kentucky, which both had double-digit declines, seven states saw the percentage of adults without insurance fall by more than 5 percentage points between 2013 and 2014.
All but one of the 11 states with the biggest drops implemented both pillars of the federal health law: expanding Medicaid coverage to low-income adults and setting up a fully or partially functioning state-based marketplace.
"While a majority of Americans continue to disapprove of the Affordable Care Act, it has clearly had an impact in reducing the uninsured rate in the U.S., which declined to its lowest point in seven years in 2014," Gallup's Dan Witters wrote in a report outlining the new findings.
Though some critics of the health law continue to question its impact on coverage, a growing number of independent surveys show the number of Americans without health insurance fell dramatically last year. The rate had been increasing in the years before the new law went into effect.
Gallup's poll is among the largest surveys on the issue, with more than 175,000 interviews annually. It found that nationwide the rate of uninsured adults declined from 17.3% in 2013 to 13.8% last year.
The lowest uninsured rates continue to be primarily in the Northeast and upper Midwest. Massachusetts, whose 2006 coverage expansion became the model for the national law, had the lowest rate at 4.6%.
The highest uninsured rates are in the South and West. For the seventh consecutive year, Texas has the worst rate in the country, with nearly a quarter of its adults uncovered.
Gallup's survey also underscored how the health law may be widening the nation's healthcare divide.
States that have fully implemented the law saw a 4.8 percentage point improvement in the share of the adult population with insurance between 2013 and 2014. That was nearly twice the rate of decline in states that have not fully implemented the law.
California, which historically had among the highest uninsured rates, recorded one of the fastest declines. The share of adults without coverage in the state fell from 21.6% to 15.3%.
Even Connecticut and Maryland, which already had among the highest rates of coverage, saw major declines in the rate of uninsured adults. Connecticut's rate dropped from 12.3% to 6%; Maryland's went from 12.9% to 7.8%
All three states have enthusiastically embraced the health law.
By contrast, Texas, where opposition to the health law has been fierce, recorded a decline of less than 3 percentage points, from 27% to 24.4%.
The Gallup survey results were based on interviews nationwide with 178,072 adults in 2013 and 176,702 adults in 2014. The margin of error is plus or minus 1 or 2 percentage points in most states, though it is closer to 4 percentage points in small states.