The percentage of U.S. adults without health insurance grew by 1.3 percentage points in 2017, or about 3.2 million people, Gallup reports, based on its Gallup-Sharecare Well-Being Index survey. This is first rise since the Affordable Care Act was enacted and the single largest increase in the uninsured rate since Gallup and Sharecare began measuring it in 2008, though at 12.2 percent uninsured it is below the peak uninsured rate of 18 percent in the third quarter of 2013, before the ACA's exchange markets and individual mandate took effect. The jump in uninsured adults was highest among young adults and Latino, black, and low-income Americans, Gallup said.

Gallup attributed the growing uninsured rate to rising premiums, insurers leaving markets, well-publicized and unsuccessful Republican attempts to repeal the ACA, more succesfull attempts to undermine it, and the common perception that the GOP would scrap the individual mandate, which they did in their tax overhaul. Republicans are looking to change the funding mechanisms for Medicaid and Medicare, and "with less federal assistance from these programs to help offset the rising cost of health insurance, fewer Americans may be able to afford health insurance," Gallup predicted. Gallup conducted more than 25,000 interviews from October through December, and the margin of sampling error is ± 1 percentage points. Peter Weber