-90.02% is the change from 812 to 81
Calculation steps:
[( 81 - 812 ) ÷ 812] x 100 = -90.02%
Formula
Percentage change = [(81 - 812) / 812] x 100
Subtract the new number by the original number
81 - 812 = -731
-731 ÷ 812 = -0.9002463054187192
-0.9002463054187192 x 100 = -90.02%