-88.24% is the change from 170 to 20
Calculation steps:
[( 20 - 170 ) ÷ 170] x 100 = -88.24%
Formula
Percentage change = [(20 - 170) / 170] x 100
Subtract the new number by the original number
20 - 170 = -150
-150 ÷ 170 = -0.8823529411764706
-0.8823529411764706 x 100 = -88.24%