-87.95% is the change from 166 to 20
Calculation steps:
[( 20 - 166 ) ÷ 166] x 100 = -87.95%
Formula
Percentage change = [(20 - 166) / 166] x 100
Subtract the new number by the original number
20 - 166 = -146
-146 ÷ 166 = -0.8795180722891566
-0.8795180722891566 x 100 = -87.95%