This is less of an idea and more of a correction that needs to be made. Our intern pointed out that the growth rate displayed at the top right of the performance chart is wrong. Here is the correct formula to use:
% increase = Increase ÷ Original Number × 100
Your formula seems to be simply growth ÷ followers × 100
So, in the attached screen grab, the percentage increase is actually 67.35% growth, not 40.25%. In this case, the percent increase formula = 14,014 (increase or followers added) ÷ 20,807 (starting or original number) × 100 = 67.35%
Your Intern is absolutely right!
Don't know how this slipped past us - but we will be correcting this asap