-98.56% is the change from 831 to 12
Calculation steps:
[( 12 - 831 ) ÷ 831] x 100 = -98.56%
Formula
Percentage change = [(12 - 831) / 831] x 100
Subtract the new number by the original number
12 - 831 = -819
-819 ÷ 831 = -0.9855595667870036
-0.9855595667870036 x 100 = -98.56%