GM letter saying they’ve updated census information for my next renewal

Really annoying that they send such a cryptic and unhelpful letter:

As part of your upcoming renewal, we want to share a brief update about a change you may notice in your policy premium.

We’ve made updates to the census information that is used when calculating rates. Your prior rate was calculated correctly with the census data used at that time; this change applies going forward with your renewal.

So they're just notifying me that my renewal rate is going to be different but can't say what it is (I'm about 60 days out from current policy expiration) and there's no way for me to see what my renewal is online currently.

I can only imagine it's going to be much higher (the rate and prices they gave were better than everyone else)

Anyone else receive the same or renew their GM insurance recently?