-23.26% is the change from 86 to 66
Calculation steps:
[( 66 - 86 ) ÷ 86] x 100 = -23.26%
Formula
Percentage change = [(66 - 86) / 86] x 100
Subtract the new number by the original number
66 - 86 = -20
-20 ÷ 86 = -0.23255813953488372
-0.23255813953488372 x 100 = -23.26%