General

Accurate explanation of drop rate system please

I've been searching for a explanation on this new drop rate system on google and in Basil BUT everyone has a different answer, like its per every level or every 5 levels that the drop rate decreases I can't seem to find anything consistent. Could anyone link me or tell me exactly the right answer to this system? I know that theres a limit where the reduction plateaus, but I need to know is it every level, per 5 level,s and how much in those increments it affects the drop rate. Much appreciated than you.