-25.2% is the change from 639 to 478
Calculation steps:
[( 478 - 639 ) ÷ 639] x 100 = -25.2%
Formula
Percentage change = [(478 - 639) / 639] x 100
Subtract the new number by the original number
478 - 639 = -161
-161 ÷ 639 = -0.2519561815336463
-0.2519561815336463 x 100 = -25.2%