-51.04% is the change from 821 to 402
Calculation steps:
[( 402 - 821 ) ÷ 821] x 100 = -51.04%
Formula
Percentage change = [(402 - 821) / 821] x 100
Subtract the new number by the original number
402 - 821 = -419
-419 ÷ 821 = -0.510353227771011
-0.510353227771011 x 100 = -51.04%