You can already pull crime statistics, nobody is stopping you from doing this - same as disease statistics. Violent crime rates have gone down, ALOT, over the past 30-40 years. With a height of 52 victims of violent crimes per 1000 people down to less than 17 victims of violent crime per 1000 people in 2009. We had less than 50 guns per 100 people in 1969, as of 2009, we are at a 1 for 1 ratio of guns to people. There went your epidemiology calculations.
You should be comparing guns and crime more to the effectiveness of a medication (the gun, in case you need a hint) on a disease (crime, you compared crime to a disease and say you can look at it as an epidemic, right?). The problem is the medication (the guns) being distributed randomly through out the population where some people have a lot of medication, some have zero medication. Now tell me the effect of this medication (guns) at curing a disease (crime) in the populace by looking ONLY at the people that are still infected (victimized). That sounds kind of dumb unless somebody was also keeping track of who used the medication (was armed) and who did not before they were infected (victimized). As far as I'm aware, we are not keeping any meaningful records on who had taken the medication (been armed) and still been infected (victimized) to even pull a small amount of data from the situation. Please, enlighten me how this all works out in your mind.
Legal gun ownership and crime[s committed by those owners] do not correlate on any meaningful level. I figured you were intelligent enough to read into the meaning, don't be ridiculous.
What is your defense now? Look somewhere else. Let me break this down easy for you. Guns don't commit crime, people commit crime. Guns can prevent crime or at least reduce the damage of a crime. This is why we call people with guns when we are in trouble.