The new report underlines the challenge that the administration faces in reaching that population.
They're trying everything: the U.S. Department of Health and Human Services announced Monday that it was launching a video contest, in tandem with the pro-reform group Young Invincibles, to publicize the new coverage options under the law. The department also awarded last week nearly $70 million in grants to "navigators," groups that will help the uninsured get covered under the law.
It should theoretically be pretty easy to make the case for coverage to young people. According to a June 2013 survey from the Kaiser Family Foundation, roughly three in four Americans ages 18 to 30 said insurance is something that they need.
But the White House also needs to get young and healthy people enrolled in coverage to make the law work financially. The Affordable Care Act prevents insurers from discriminating against sick and older people who want to get insured, a population that is likely to cost insurers more, so companies need young and healthy people to pay into the system to offset that new spending.
If they don't, and costs go up for insurers, those costs will be passed onto their customers, driving up the overall price of insurance.