@Setanta,
My math doesn't suck. Maybe my opinion does but you're the one recalculating over and over. (But you did admit your math sucks)
I'm not sure what the number you've finally settled on is but since it is far beyond even 5%, you've made the case that the incidents are statistically rare.
This is a question of risk assessment.
Since there is no way on earth that we can be protected from all risks; all danger we need to examine each threat in terms of its likelihood.
Driving in a car is, statistically, more dangerous than gun ownership.
No one has even dreamed of outlawing cars even though there have been incidents where drivers have used their cars as weapons. (A few Islamist attacks come to mind).
We have a constitutionally protected right to own guns. If someone doesn't like that, change the constitution, and then you can move on to knives.