-97.42% is the change from 813 to 21
Calculation steps:
[( 21 - 813 ) ÷ 813] x 100 = -97.42%
Formula
Percentage change = [(21 - 813) / 813] x 100
Subtract the new number by the original number
21 - 813 = -792
-792 ÷ 813 = -0.974169741697417
-0.974169741697417 x 100 = -97.42%