-99.22% is the change from 640 to 5
Calculation steps:
[( 5 - 640 ) ÷ 640] x 100 = -99.22%
Formula
Percentage change = [(5 - 640) / 640] x 100
Subtract the new number by the original number
5 - 640 = -635
-635 ÷ 640 = -0.9921875
-0.9921875 x 100 = -99.22%