-68.13% is the change from 800 to 255
Calculation steps:
[( 255 - 800 ) ÷ 800] x 100 = -68.13%
Formula
Percentage change = [(255 - 800) / 800] x 100
Subtract the new number by the original number
255 - 800 = -545
-545 ÷ 800 = -0.68125
-0.68125 x 100 = -68.13%