-68.39% is the change from 639 to 202
Calculation steps:
[( 202 - 639 ) ÷ 639] x 100 = -68.39%
Formula
Percentage change = [(202 - 639) / 639] x 100
Subtract the new number by the original number
202 - 639 = -437
-437 ÷ 639 = -0.6838810641627543
-0.6838810641627543 x 100 = -68.39%