-93.28% is the change from 640 to 43
Calculation steps:
[( 43 - 640 ) ÷ 640] x 100 = -93.28%
Formula
Percentage change = [(43 - 640) / 640] x 100
Subtract the new number by the original number
43 - 640 = -597
-597 ÷ 640 = -0.9328125
-0.9328125 x 100 = -93.28%