My folks live in North Carolina and hear it at least once/week.
So in the 3 minutes that elapsed from the time I made my post, you had time to call your parents, have them tally how often they hear the "n" word, then report it to HROT. Or maybe they call you up every time they hear it in you keep a tally for yourself. Either way, I'd say the odds are pretty favorable you're making numbers up as well.
And FWIW, I'd say the frequency of which I hear the "n" word is pretty consistent between Iowa and the south. Iowa isn't even close to the melting pot of diversity many of it's residents would like to proclaim it as being.