-68.63% is the change from 816 to 256
Calculation steps:
[( 256 - 816 ) ÷ 816] x 100 = -68.63%
Formula
Percentage change = [(256 - 816) / 816] x 100
Subtract the new number by the original number
256 - 816 = -560
-560 ÷ 816 = -0.6862745098039216
-0.6862745098039216 x 100 = -68.63%