-86.42% is the change from 81 to 11
Calculation steps:
[( 11 - 81 ) ÷ 81] x 100 = -86.42%
Formula
Percentage change = [(11 - 81) / 81] x 100
Subtract the new number by the original number
11 - 81 = -70
-70 ÷ 81 = -0.8641975308641975
-0.8641975308641975 x 100 = -86.42%