michigan insurance credit scoring

I live in Michigan, why rates insurance companies ???????? based on credit scores ???????? is this LEGAL
If so why !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! help especially in this economy ……
Actuarial studies show that how a person handles their financial affairs, which is what indicates an insurance score is a good predictor of claims insurance. Statistically, people with lower scores in insurance claims tend to have more.
Sen. Martha G. Scott Rally for Fair Affordable Insurance MI