-89.49% is the change from 866 to 91
Calculation steps:
[( 91 - 866 ) ÷ 866] x 100 = -89.49%
Formula
Percentage change = [(91 - 866) / 866] x 100
Subtract the new number by the original number
91 - 866 = -775
-775 ÷ 866 = -0.894919168591224
-0.894919168591224 x 100 = -89.49%