Following Ohio in the Swear Rankings were Maryland, New Jersey, Louisiana and Illinois.
Louisiana, oddly enough, turns up as one of the most courteous states as well, based on related data that tracked usage of "please" and "thank you" and other fundamental staples of spoken etiquette. Southern hospitality appears to be alive and well, though; the other ultra-courteous states were South Carolina, North Carolina, Maryland and Georgia.
Also, it turns out that the longer you're on the phone with a shitty customer service rep, the more likely you are to swear. Go figure.