-18.71% is the change from 171 to 139
Calculation steps:
[( 139 - 171 ) ÷ 171] x 100 = -18.71%
Formula
Percentage change = [(139 - 171) / 171] x 100
Subtract the new number by the original number
139 - 171 = -32
-32 ÷ 171 = -0.1871345029239766
-0.1871345029239766 x 100 = -18.71%