-88.45% is the change from 866 to 100
Calculation steps:
[( 100 - 866 ) ÷ 866] x 100 = -88.45%
Formula
Percentage change = [(100 - 866) / 866] x 100
Subtract the new number by the original number
100 - 866 = -766
-766 ÷ 866 = -0.8845265588914549
-0.8845265588914549 x 100 = -88.45%