-70.44% is the change from 866 to 256
Calculation steps:
[( 256 - 866 ) ÷ 866] x 100 = -70.44%
Formula
Percentage change = [(256 - 866) / 866] x 100
Subtract the new number by the original number
256 - 866 = -610
-610 ÷ 866 = -0.7043879907621247
-0.7043879907621247 x 100 = -70.44%