New findings from CDC’s National Health Interview Survey show the uninsured rate at its lowest level since the agency started tracking this statistic 17 years ago. In the first quarter of 2014, an estimated 13.1% of the US population did not have health insurance at the time of interview. That figure was 15.4% in 1997, and rose to 16.0% in 2010 before it began falling.

Vox’s Sarah Kliff points out that the percentage of US children without health insurance has dropped more dramatically than that of the US population as a whole, from 13.9% in 1997 to 6.6% in 2014. Much of the credit for that decrease goes to the Children’s Health Insurance Program.

Uninsurance rates have also declined more substantially for the poor and near-poor than for those not living in poverty. In 2009, 30.2% of those with incomes under 100% of the federal poverty level and 29.4% of those with incomes between 100% and 200% FPL were uninsured, compared to 10.7% of those with incomes above 200% FPL. In early 2014, 24.1% of the poor, 26.2% of the near-poor, and 9.0% of the not-poor were uninsured at the time of interview. (For 2014, the federal poverty level is $11,670 for one person and and $23,850 for a four-person household, so even the “not-poor” income of 200% FPL will leave many families struggling.)

CDC’s report on the new NHIS findings highlights the differences between states that accepted the Affordable Care Act’s Medicaid expansion (which the Supreme Court made optional) and those that didn’t. The researchers found that in states that expanded Medicaid, the percentage of uninsured adults ages 18-64 fell from 18.4% in 2013 to 15.7% in the first quarter of 2014. They found no such significant decrease in the states not accepting the Medicaid expansion.

It’s still shameful that 13% of people in one of the world’s wealthiest nations don’t have health insurance coverage. But at least things are moving in the right direction.