-80.83% is the change from 866 to 166
Calculation steps:
[( 166 - 866 ) ÷ 866] x 100 = -80.83%
Formula
Percentage change = [(166 - 866) / 866] x 100
Subtract the new number by the original number
166 - 866 = -700
-700 ÷ 866 = -0.8083140877598153
-0.8083140877598153 x 100 = -80.83%