-49.41% is the change from 170 to 86
Calculation steps:
[( 86 - 170 ) ÷ 170] x 100 = -49.41%
Formula
Percentage change = [(86 - 170) / 170] x 100
Subtract the new number by the original number
86 - 170 = -84
-84 ÷ 170 = -0.49411764705882355
-0.49411764705882355 x 100 = -49.41%