Datatable - display computed value from previous column

How to get the percentage of a particular column in datatable of visualization in kibana?
In my table, I have 3 columns.
Kibana 7.3.2

Col A: Text
Col B: Volume of something (numeric)
Col C: ?? (should be percentage based on Col B)

If you click on "Options" there is a "Percentage column" you can include. Is that accomplish what you're looking for?

I believe you have misunderstood my question. Let me rephrase, I need a new column with the percentage of the row values. Example : Col B containing value of 200, then Col C should be 80% of the value of Col B which is 160.
Also I find no "Percentage column" under "Options".