Information and ranking management of an Adobe Stock author account

Hi to the whole community, 
I apologize for my English but I am Italian, the question is as follows:

I would like to know what is the periodicity, the frequency with which the rankings of a Contributor account on Adobe Stock
 (white, bronze etc etc.) are reviewed and modified, perhaps every year? 
I ask the most experienced.

Greetings to the whole community

Sebàstian C.