The share of U.S. adults without health insurance rose by 1.3 percentage points, or an estimated 3.2 million people, in 2017 to 12.2%, according to the Gallup-Sharecare Well-Being Index. That’s the largest increase since the index began tracking the adult uninsured rate in 2008, but well below the peak rate of 18% before the Affordable Care Act’s Health Insurance Marketplaces opened in October 2013, Gallup notes. According to the index, the rate rose for all demographic groups except adults aged 65 and older, with the largest increases among young, black, Hispanic and low-income Americans.