The Long-Term Uninsured in America report is useful for historical reference. It analyzes the number of people under age 65 without insurance, before Obamacare expanded coverage in 2014. Using MEPS data, the largest segments of US population without health insurance for 4 years (2009-2012) included Hispanics (18.5% of the under-65 population, but 42.2% of the 4-year uninsured); the Poor Income group (17.5% of population, but 27.2% of long-term uninsured); those in Fair/Poor Health (11.1% compared to those in Excellent Health at 6.1%) and 25-29 year olds (15.8% rate). AHRQ Statistical Brief #464, Dec. 2014