Your literature is replete with examples of countries which first registered firearms, then used those lists to confiscate them. This requires research, and might lead to an interesting article in the future. More importantly, the argument will never be won on mere statistical comparisons. Stats don't mean anything when it comes to events of this sort. Just because a particular atrocity hasn't happened yet does not in any way predict the future.
Firearms ownership is a protection and deterrent.
It is not merely a response to previous event. They ought to be paying for the protection.