-67.29% is the change from 639 to 209
Calculation steps:
[( 209 - 639 ) ÷ 639] x 100 = -67.29%
Formula
Percentage change = [(209 - 639) / 639] x 100
Subtract the new number by the original number
209 - 639 = -430
-430 ÷ 639 = -0.672926447574335
-0.672926447574335 x 100 = -67.29%