-19.88% is the change from 171 to 137
Calculation steps:
[( 137 - 171 ) ÷ 171] x 100 = -19.88%
Formula
Percentage change = [(137 - 171) / 171] x 100
Subtract the new number by the original number
137 - 171 = -34
-34 ÷ 171 = -0.19883040935672514
-0.19883040935672514 x 100 = -19.88%