I am trying to create a line+grouped bar card where date is set by month to show the % change in opportunities overall at the same times as the count of opportunities.
The grouped bars measure how many opportnities were created by channel i.e., each bar represents how many opportunties came from digital, referrals, etc.
The light blue trend line in the attached image currently shows the total number of opportunities and as a result it is simply the sum of all opportunities created from different channels.
What I want to do— and I am not even sure if it's possible— is to use the datapoints of the line to calculate the percent change in opportunities each month. I know that there can be two measures for the y-axis, and I need the left to be the % change and the right hand side to be the count of opportunities. Setting up the axes is not my question, but rather how I can use cases for the month to calcualte this. The issue is that I do not have a measurement for total number of opportunities by month; it is being generated when I set the COUNT of opportunities into the graph
pseudo-code which describes what I need:
"percent change this month"
100*[(count all opportunities in thismonth - (count of all opportunities in thismonth-1)) / count of all opportunities in thismonth-1]