-99.07% is the change from 642 to 6
Calculation steps:
[( 6 - 642 ) ÷ 642] x 100 = -99.07%
Formula
Percentage change = [(6 - 642) / 642] x 100
Subtract the new number by the original number
6 - 642 = -636
-636 ÷ 642 = -0.9906542056074766
-0.9906542056074766 x 100 = -99.07%