-97.98% is the change from 642 to 13
Calculation steps:
[( 13 - 642 ) ÷ 642] x 100 = -97.98%
Formula
Percentage change = [(13 - 642) / 642] x 100
Subtract the new number by the original number
13 - 642 = -629
-629 ÷ 642 = -0.9797507788161994
-0.9797507788161994 x 100 = -97.98%