-69.8% is the change from 639 to 193
Calculation steps:
[( 193 - 639 ) ÷ 639] x 100 = -69.8%
Formula
Percentage change = [(193 - 639) / 639] x 100
Subtract the new number by the original number
193 - 639 = -446
-446 ÷ 639 = -0.6979655712050078
-0.6979655712050078 x 100 = -69.8%