Car Insurance Rates After Accident

How do car accidents affect insurance rates?
I live in Massachusetts and have Progressive insurance. Over the past three years, I have been involved in 3 at-fault accidents. The dates were: 3/2006, 12/2006, and 12/2009. I know my insurance premiums will rise after my most recent accident. My questions are: How much will they rise? (i.e. What $ amount will I be paying monthly?) and when will the 2006 accidents cease to affect my insurance rates now that it is 2010?
You can compare how the insurance quotes would change, for example here – autoinsurance.noneto.com
Steps to Take After a Traffic Accident
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