Player rating for tournaments across all installments of Heroes.

Could you clarify a small point regarding the aging system? Does the current rating age, or is it the annual rating that ages? Is the annual rating simply the sum of the current ratings? If so, then the annual rating also ages. Wouldn't it be simpler to do this: the rating doesn't age, but it resets every year. And the player's profile (or the final table) would display the results from the previous year.