-68.82% is the change from 821 to 256
Calculation steps:
[( 256 - 821 ) ÷ 821] x 100 = -68.82%
Formula
Percentage change = [(256 - 821) / 821] x 100
Subtract the new number by the original number
256 - 821 = -565
-565 ÷ 821 = -0.6881851400730816
-0.6881851400730816 x 100 = -68.82%