-73.53% is the change from 646 to 171
Calculation steps:
[( 171 - 646 ) ÷ 646] x 100 = -73.53%
Formula
Percentage change = [(171 - 646) / 646] x 100
Subtract the new number by the original number
171 - 646 = -475
-475 ÷ 646 = -0.7352941176470589
-0.7352941176470589 x 100 = -73.53%