This will vary widely depending upon what your thoughts are on the current economic/political environment and possible outcomes.
I'm sure most of you remember hearing something about riots in LA back in '92?
Several sources (that I can't find just now ) over the years since have claimed that several Korean shopkeepers in South Central went through about 500 rounds a day to ward off the mobs. Of course, that number likely would have been smaller had they been aiming for something more than to scare in most cases.
However, the question remains, how many days will it take for the S to "un-hit" the F?
My spare bedroom is completely full of ammo. I would take a picture, but then the people with tin foil hats will come to get me. That way I can defend the whole city of columbus by myself