-89.75% is the change from 878 to 90
Calculation steps:
[( 90 - 878 ) ÷ 878] x 100 = -89.75%
Formula
Percentage change = [(90 - 878) / 878] x 100
Subtract the new number by the original number
90 - 878 = -788
-788 ÷ 878 = -0.89749430523918
-0.89749430523918 x 100 = -89.75%