Sorry to disappoint you, Francois, but these numbers are not even published officially, they are part of THE SECRET. So how would it be justified to add an official indicator?
The closest hint ever given by mods are links to users' postings containing the numbers, stating that these are "good guesses".
And, user's workaround is quite simple: Until Tour Pro tier, count the rounds in the score history, and from Master tier on, make a note of the ranked rounds in the stats somewhere when you tier up.
And, for most of us it doesn't really matter, because the average drops slower. It's only an intermediate landmark to pass saturatiion, and you'd notice it anyway.
Most of all, this site ain't about labour where numbers and allowances would prevail, but here rUleZ fun and leisure - enjoy the games, the pictures, the company!!