-84.45% is the change from 643 to 100
Calculation steps:
[( 100 - 643 ) ÷ 643] x 100 = -84.45%
Formula
Percentage change = [(100 - 643) / 643] x 100
Subtract the new number by the original number
100 - 643 = -543
-543 ÷ 643 = -0.8444790046656299
-0.8444790046656299 x 100 = -84.45%