-89.15% is the change from 839 to 91
Calculation steps:
[( 91 - 839 ) ÷ 839] x 100 = -89.15%
Formula
Percentage change = [(91 - 839) / 839] x 100
Subtract the new number by the original number
91 - 839 = -748
-748 ÷ 839 = -0.8915375446960667
-0.8915375446960667 x 100 = -89.15%