This is an interesting article because it gives us some insight into how pet insurance companies use actuarial data when setting premiums for their policies. I don't actually know a lot about it, but when I've asked questions of pet insurance company representatives about their company's actuarial data, they are usually very secretive when it comes to discussing specifics.
In fact, companies use this data to adjust premiums from time to time. If you receive a notice that your premium is going up or down, this is probably the reason. I've read in the past year that some pet owners found that their premiums increased as much as 50%, and I've also read where some pet owners (same company) received the news that their premium actually decreased slightly.