Yup, what Granite said.
Both of the Dakotas and Wyoming have stayed relatively low, but we're feeling the pinch. Our state unemployment rate is 3.9% right now and that's up from about 3%. It was only 2.3% in Sx. Falls a few months ago. Of course, the smaller towns would have a higher unemployment rate.
Diverse~I mean that in the fact that we have a lot of different jobs/occupations. And we do have factories here, but one of the things several have chosen to do is to drop their employees to 32 hrs. per week rather then laying some people off. It helps the employee still have their job and keep their health insurance, etc. Cheers to the fact that many of our employers have compassion for their employees
Along with the good business climate that Granite listed, we have the rep for having a good work ethic~the Midwestern work ethic. I honestly don't know how true it is, but often when someone leaves here, employers seem to love the fact that we generally show up for work, we're on time, we work when we're on the job, etc. It seems to be an added plus that perspective companies look at when moving to our state.
Lack of unions~we're a right to work state and there are very few unions here. Of course, the meatpacking plant has one, Homestake used to have one, the teachers have one, etc., but they're far and few between. It makes for a good business climate because we don't DEMAND high wages and it hopefully keeps more companies in business. (just an observation, not a debate)
Our states aren't considered to be desireable like some of the southern/western states are. Of course, anyone who has vacationed in the Black Hills or at Yellowstone loves it here, but our climate is a deterrent so people don't flock here.
I'd guess there are several more reasons, but those are the ones that just popped into my mind.