-70.13% is the change from 857 to 256
Calculation steps:
[( 256 - 857 ) ÷ 857] x 100 = -70.13%
Formula
Percentage change = [(256 - 857) / 857] x 100
Subtract the new number by the original number
256 - 857 = -601
-601 ÷ 857 = -0.7012835472578763
-0.7012835472578763 x 100 = -70.13%