There are various factors that are considered for each policy holder AND THEN there's also your location that seems to make a very big impact. This is likely why we see such a big delta between those reported.
To add, I've had preminums change significantly after underwriting changes the way they eval things. So it's also best to do an audit once in awhile. I was a loyal State Farm policy holder, but the last few years they've been significantly raising rates very year while I've made NO claims in the last 20 years (essentially I'm paying for others claims......)
In summary, it's best to shop ALL the insurance companies and evaluate which one fits best for you (terms, conditions, pricing).
