What's behind the rates? According to Insure.com, the varying laws in each state are partly to blame as is the state' population. From today's New York Times:
According to Insure.com, states’ different laws are partly to blame. “Our findings show that the financial ramifications of specific state laws and regulations are driving high rates in certain states,” Amy Danise, senior managing editor of Insure.com, said in a statement. “No matter how good your own driving record is, you’re paying for the decisions of lawmakers.”
Washington state came in between Nevada and Utah. See the full report here.