-87.16% is the change from 631 to 81
Calculation steps:
[( 81 - 631 ) ÷ 631] x 100 = -87.16%
Formula
Percentage change = [(81 - 631) / 631] x 100
Subtract the new number by the original number
81 - 631 = -550
-550 ÷ 631 = -0.8716323296354992
-0.8716323296354992 x 100 = -87.16%