The obvious thing that would correlate with the south would be average household income. Not all of these mobile only households are carrying $70/mo voice+unlim

The obvious thing that would correlate with the south would be average household income. Not all of these mobile only households are carrying $70/mo voice+unlimited text+large 3g quota plans, many of them are likely on $5-$15/mo prepaid options because they are cheaper than carrying a landline.