-70.09% is the change from 866 to 259
Calculation steps:
[( 259 - 866 ) ÷ 866] x 100 = -70.09%
Formula
Percentage change = [(259 - 866) / 866] x 100
Subtract the new number by the original number
259 - 866 = -607
-607 ÷ 866 = -0.7009237875288684
-0.7009237875288684 x 100 = -70.09%