The uninsured rate sunk to a record low of 9.1 percent in 2015, according to a new CDC survey.

Though 28.6 million Americans remained uninsured in 2015, the number has decreased since the broadest provisions of the Affordable Care Act went into effect. In 2013, the total number of uninsured stood at 44.8 million people.

Uninsured rates dropped among all groups measured in the survey: children up until age 17 (5.5 percent in 2014 to 4.5 percent in 2015), adults 18 to 64 (16.3 percent to 12.2 percent), people at or below the poverty line (22.3 percent to 17.2 percent), Hispanics or Latinos (25.2 percent to 20.8 percent), African-Americans (13.5 percent to 11.2 percent), Asian-Americans (10.6 percent to 6.7 percent) and whites (9.8 percent to 7.4 percent).

Looking at larger trends based off provisions of the Affordable Care Act, the survey said insurance enrollment differed significantly depending on whether states expanded Medicaid and what kind of health insurance marketplace was available.  

In the 31 Medicaid expansion states, the number of uninsured under 65 years of age dropped from 14.9 percent in 2013 to 8.2 percent in 2015. In the 19 non-expansion states, the numbers also fell, but remain higher: 14 percent were uninsured in 2015, down from 18.4 percent in 2013.

For marketplaces, uninsured rates were higher in states that rely on the federal marketplace compared to a state-run or partnership exchange. In state-based marketplace states, 7.7 percent of individuals were without insurance in 2015, down from 15.2 percent in 2013. Partnership marketplace states saw a decline from 14.2 percent uninsured in 2013 to 8 percent in 2015, while federally facilitated marketplace states had 12.8 percent uninsured, a drop from 17.9 percent in 2013.

The survey also found continuing changes in people who are insured outside the ACA marketplaces. Among people who are enrolled in high-deductible health plans, 36.6 percent are getting their coverage through their employer, up from 23.3 percent in 2010. Fewer are purchasing such plans directly (50.9 percent, down from a high of 56.4 percent in 2013).

Among individual states, Texas had the highest rate of uninsured among those under age 65 (18.8 percent), while Massachusetts had the lowest (2.9 percent). North Dakota had the lowest number on public health plans (11.4 percent), and New Mexico had the highest (43.8 percent), while also having the lowest rate of private health coverage (46.1 percent). New Jersey had the highest rate of private coverage at 75.9 percent.