-39.88% is the change from 820 to 493
Calculation steps:
[( 493 - 820 ) ÷ 820] x 100 = -39.88%
Formula
Percentage change = [(493 - 820) / 820] x 100
Subtract the new number by the original number
493 - 820 = -327
-327 ÷ 820 = -0.39878048780487807
-0.39878048780487807 x 100 = -39.88%