-18.24% is the change from 170 to 139
Calculation steps:
[( 139 - 170 ) ÷ 170] x 100 = -18.24%
Formula
Percentage change = [(139 - 170) / 170] x 100
Subtract the new number by the original number
139 - 170 = -31
-31 ÷ 170 = -0.18235294117647058
-0.18235294117647058 x 100 = -18.24%