According to some analysts, the reason is beaurocratic... Isn't everything though?! Different crimes are categorized, reported, and therefore affect crime statistics differently from state to state. Analyzing Chicago, New York City, or Los Angeles crime rates one would expect them to be much different than a place like Greenville... and they SHOULD BE (I've lived in LA & NYC) and I've lived in Simpsonvillve, a suburb of Greenville for 2 1/2 years. Don't let the crime rates deter you! Greenville is a breath of fresh air, a beautiful and safe place to live! I love and highly recommend it.
Because the stats include an "inner city" area of Greenville that have virtually no impact on you if you live in the suburbs. Crime is actually very low for the most part if you are living in a typical middle class neighborhood in this region. The other influence is the extremely poor rural areas.
For the average person, this is an outstanding place to live and raise children.