How is it, you think that you can disprove something with the same argument, that you used to say can't be used for proving?
I live in a Country where guns are banned, and you know what? Crime with guns are exceedingly rare; they are hard to come by and aren't needed - if you want to rob someone, chances are they aren't carrying any kind of weapon and will give up their cash without problems.
Now obviously you paranoid 'Muicans will think that this is a bad thing, allowing yourself getting robbed - but truth is, we have lower crime rate than you guys *and* when someone does get robbed and choose to fight, they have a way better chance of survival than your gun shot victims.
By the ways, those "statistics" you mention, they are from the same period of time, where lead was dropped from gasoline, which has been *shown* to cause aggression and violence.