With numbers current to January 16, 2016; there were approximately 12,800,000 valid Concealed W Carry Weapons (CCW) permits, sometimes called Licenses to Carry or LTC’s.
It should be kept in mind that some jurisdictions refuse to provide the number of licenses issued or the number of licenses still valid. Given that, the 12,800,000 total may be as much as 1,700,000 short of the actual total.
It should also be kept in mind that many States allow open carry without a permit, and a number of States, including Arizona, Alaska, Vermont, and Wyoming allow concealed carry without a permit for in state carry.
All in all, well over twenty million adult Americans could legally carry, either openly or concealed at this time.