-56.34% is the change from 639 to 279
Calculation steps:
[( 279 - 639 ) ÷ 639] x 100 = -56.34%
Formula
Percentage change = [(279 - 639) / 639] x 100
Subtract the new number by the original number
279 - 639 = -360
-360 ÷ 639 = -0.5633802816901409
-0.5633802816901409 x 100 = -56.34%