-25.47% is the change from 640 to 477
Calculation steps:
[( 477 - 640 ) ÷ 640] x 100 = -25.47%
Formula
Percentage change = [(477 - 640) / 640] x 100
Subtract the new number by the original number
477 - 640 = -163
-163 ÷ 640 = -0.2546875
-0.2546875 x 100 = -25.47%