-99.38% is the change from 642 to 4
Calculation steps:
[( 4 - 642 ) ÷ 642] x 100 = -99.38%
Formula
Percentage change = [(4 - 642) / 642] x 100
Subtract the new number by the original number
4 - 642 = -638
-638 ÷ 642 = -0.9937694704049844
-0.9937694704049844 x 100 = -99.38%