Cumulative Counts with rolling percentages

I have a dashboard where I have added 2 charts into the same chart because Im having trouble figuring out how to do cumulative counts and have a rolling percentage along side it

How do I have it so that I can show a cumulative count AND the relative % in the same question?

Im currently using the dashboard to join the two question results. When I try to use the "join" feature in the UI, I get an error

Ideal outcome:
Month | Cumulative Count of Users | Users who Post (shown as % of cumulative users)

Eg:

Jan 2021 | 100 | 10%
Feb 2021 | 150 | 15%
Mar 2021 | 190 | 16%
etc etc

This is what it looks like when I combine the two questions via the Dashboard instead of using the Join feature in the query editor

Hi @jins-agridigital
Cumulative functions doesn't work like other functions. You are seeing this issue:
https://github.com/metabase/metabase/issues/13634 - upvote by clicking :+1: on the first post