This report shows that, since September 2010 – when adults aged 19–25 were able to obtain dependent private health insurance coverage through a provision of the ACA – the percentage of young adults with private insurance increased and the percentage without insurance decreased. The increase in the percentage with private insurance occurred at about the same time (January–June 2011) as a temporary increase in the percentage of privately insured young adults who had been uninsured at some time in the past 12 months. This suggests that those newly insured were previously uninsured or had a period of no insurance in the past year. After this spike, the percentage of young adults with a period of no insurance did not return to pre-2011 levels but rather declined to levels consistent with slightly older adults. The data comes from the National Health Interview Survey, 2008–2012.