-74.8% is the change from 639 to 161
Calculation steps:
[( 161 - 639 ) ÷ 639] x 100 = -74.8%
Formula
Percentage change = [(161 - 639) / 639] x 100
Subtract the new number by the original number
161 - 639 = -478
-478 ÷ 639 = -0.7480438184663537
-0.7480438184663537 x 100 = -74.8%