-39.95% is the change from 821 to 493
Calculation steps:
[( 493 - 821 ) ÷ 821] x 100 = -39.95%
Formula
Percentage change = [(493 - 821) / 821] x 100
Subtract the new number by the original number
493 - 821 = -328
-328 ÷ 821 = -0.3995127892813642
-0.3995127892813642 x 100 = -39.95%