Rey, I too have 21st Century here in Arizona. I just received a renewal and my rates stayed the exactly same.
But I should also comment that I have not had rates drop during the time I owned a vehicle for many years. This has always seemed like a ripoff to me. Yes it still costs the same to repair the vehicle regardless of age. But if I experience a total loss, the reimbursement will only be the fair market value of my vehicle, which is far less than when it was brand new.
Tom