-97.05% is the change from 643 to 19
Calculation steps:
[( 19 - 643 ) ÷ 643] x 100 = -97.05%
Formula
Percentage change = [(19 - 643) / 643] x 100
Subtract the new number by the original number
19 - 643 = -624
-624 ÷ 643 = -0.9704510108864697
-0.9704510108864697 x 100 = -97.05%