The Today's Prices page uses fixed example pet profiles to show how quotes can change. Fixed profiles matter because they keep the comparison steadier. If the dog, cat, age, postcode and cover choices changed every time, it would be much harder to see whether prices were really moving.
Pet insurance premiums in the UK are affected by veterinary costs, claims trends, inflation, competition between insurers and the age and breed of the pet being insured. Vet fees have risen sharply in recent years, and that feeds into the cost of claims. When claims become more expensive, premiums often follow.
Price history should not be read as a prediction of your own quote. Your premium may be higher or lower depending on your pet and the policy you choose. What it can do is show the direction of travel and help explain why renewals sometimes feel very different from one year to the next.
Use price history as context, then read the policy wording carefully before buying.