-6.58% is the change from 866 to 809
Calculation steps:
[( 809 - 866 ) ÷ 866] x 100 = -6.58%
Formula
Percentage change = [(809 - 866) / 866] x 100
Subtract the new number by the original number
809 - 866 = -57
-57 ÷ 866 = -0.06581986143187067
-0.06581986143187067 x 100 = -6.58%