While Colorado's rate of 34.3% is in the ball park, I understand the nature of this study involves a lot of estimation.
However, this is disclosed in
the study's methodology, which states:
Here is a look at per capita weapons data, based on the ATF's National Firearms Registration and Transfer Record, and 2013 data from the U.S. Census.
While the ATF's National Firearms Registration and Transfer Record is the only accessible list of its kind, it is not all-inclusive. NFA firearms only include the categories regulated by The National Firearms Act of 1934: machine guns, short-barreled rifles, short-barreled shotguns, suppressors, destructive devices like bombs and grenades, concealable devices with the ability to discharge a shot through the energy of an explosive, and any firearm with a bore over half an inch that has not been determined to have a legitimate sporting use.
But some guns fall outside of this scope, and many aren't registered, meaning surveys on gun ownership come to different conclusions.
It's OK that we don't have highly accurate numbers. Decent approximations are all we need. Whether 80 million gun owners, 104 million, or 120 million, the point remains the same: We are not few in number!