-83.95% is the change from 866 to 139
Calculation steps:
[( 139 - 866 ) ÷ 866] x 100 = -83.95%
Formula
Percentage change = [(139 - 866) / 866] x 100
Subtract the new number by the original number
139 - 866 = -727
-727 ÷ 866 = -0.8394919168591224
-0.8394919168591224 x 100 = -83.95%