-90.22% is the change from 828 to 81
Calculation steps:
[( 81 - 828 ) ÷ 828] x 100 = -90.22%
Formula
Percentage change = [(81 - 828) / 828] x 100
Subtract the new number by the original number
81 - 828 = -747
-747 ÷ 828 = -0.9021739130434783
-0.9021739130434783 x 100 = -90.22%