-90.16% is the change from 823 to 81
Calculation steps:
[( 81 - 823 ) ÷ 823] x 100 = -90.16%
Formula
Percentage change = [(81 - 823) / 823] x 100
Subtract the new number by the original number
81 - 823 = -742
-742 ÷ 823 = -0.9015795868772782
-0.9015795868772782 x 100 = -90.16%