What percentage are you trying to calculate. For example the % gain in September 2017 is relative to what? Previous month, parameter month, previous year?
For this example I'd like to compare my snapshots of whats in the workbook. Can we find the percentage difference from current month MTD of sales compared to previous month MTD of sales?
That is 81%. I guess the "% Gained" should be -19%. So -19% is what I am looking for. But I could get that from finding the 81% as well.