-98.75% is the change from 640 to 8
Calculation steps:
[( 8 - 640 ) ÷ 640] x 100 = -98.75%
Formula
Percentage change = [(8 - 640) / 640] x 100
Subtract the new number by the original number
8 - 640 = -632
-632 ÷ 640 = -0.9875
-0.9875 x 100 = -98.75%
Example