-0.81% is the change from 866 to 859
Calculation steps:
[( 859 - 866 ) ÷ 866] x 100 = -0.81%
Formula
Percentage change = [(859 - 866) / 866] x 100
Subtract the new number by the original number
859 - 866 = -7
-7 ÷ 866 = -0.008083140877598153
-0.008083140877598153 x 100 = -0.81%