The CDC has released their initial 2015 uninsured population counts. Good news, for all residents of the US in the US through September 2015. Remember, this percentage will go down a bit more as Montana and Alaska are expanding Medicaid and the 2016 Open Enrollment period pulled in more people.
These numbers are a bit lower than Gallup and other sources because this data set includes kids and the elderly. Both of those groups tend to have a higher insurance rate because there are more government programs aimed at those two populations. Working age adults have a slightly higher than national average uninsured rate.