Half the spam calls I've gotten have a 1/10,000 chance of being local to me by using the same area and exchange code - XXX-XXX-????. About 1/4 use the same area code, so 1/10,000,000. The other 1/4 are in that 1/10bil chance. Still, unlikely since there aren't too many in the 1/10k bucket with reason to call me, but it's important to not misrepresent the majority of calls having odds off by 3 magnitudes.