-97.71% is the change from 831 to 19
Calculation steps:
[( 19 - 831 ) ÷ 831] x 100 = -97.71%
Formula
Percentage change = [(19 - 831) / 831] x 100
Subtract the new number by the original number
19 - 831 = -812
-812 ÷ 831 = -0.9771359807460891
-0.9771359807460891 x 100 = -97.71%