DAX FUNCTION FOR TIERS?

With the data that I have, is there a way to create a column that tiers the Gross Chargbacks in tiers of 20%? I want the highest dollar value to be placed in the first 20% and so on. These tiers should be represented by a score of 1,2,3,4 and 5, with the first 20% being a 1.

I also have a date table in which I am joing to, that has the fiscal years. I want each fiscal year to be tiered. In other words I do not want the entire table to be tiered at once, rather I want to have a 20% tiered projection, one fiscal year at a time. Is there a way to do this?