The percentage of young adults in the United States who lack health insurance has declined since the end of 2010, when the provision of Obamacare that allowed those up to age 25 to stay on their parents' plans went into effect, according to second-quarter results from theGallup-Healthways Well-Being IndexHowever, the uninsured rate for adults ages 26 to 64 has steadily risen, from about 15 percent in 2008 to 19.6 percent currently. Overall, an average of 17.2 percent of U.S. adults were uninsured in the second quarter of 2013, similar to levels found in 2011 and 2012. Though the requirement that employers with at least 50 full-time workers provide health insurance is delayed for a year, individuals will still be able to purchase coverage through electronic marketplaces run by the states or federal government beginning Oct. 1.