-68.4% is the change from 810 to 256
Calculation steps:
[( 256 - 810 ) ÷ 810] x 100 = -68.4%
Formula
Percentage change = [(256 - 810) / 810] x 100
Subtract the new number by the original number
256 - 810 = -554
-554 ÷ 810 = -0.6839506172839506
-0.6839506172839506 x 100 = -68.4%