Without testing on my end :
// exact match
sum(if [Reason] = 'The brand name' then 1 else 0 end)/total([Reason])
sum(if find([Reason],'The brand name') > 0 then 1 else 0 end)/total([Reason])
To help you partially for your query, I am seeing a line in your question stating that:
I essence, I want to count how many times 'The brand name' Comes up
For this thing, I am attaching a Workbook which will clearly show you how to count the occurance of particular words!
once this count is there, just calculate the percent of total.
Hope it will help you a bit.
Word Count.twbx 51.3 KB
Thanks heaps, that has worked great.