[notahacker]

If you're not content taking your bogus statistics from the sort of blog with so little handle on reality it described Bloomberg as a "communist organisation", you can read the actual report

It excludes mass shootings if the shooters were gang members or robbers, if the victims were in [multiple] private homes, if concealed carry permits weren't handed out like candy in the local area or if the heavily armed guards in place throughout the incident were naval officers or law enforcement officials stationed there to stop shootings....

Trouble is, once you've concluded armed guards were shot because they were "gun free", anywhere where concealed carry isn't commonplace is also "gun free" and mass shootings in private homes don't matter to analysis of gun owners' ability to defend themselves you've probably concluded that rather more than 92% of the US population are in gun free areas...