-89.31% is the change from 851 to 91
Calculation steps:
[( 91 - 851 ) ÷ 851] x 100 = -89.31%
Formula
Percentage change = [(91 - 851) / 851] x 100
Subtract the new number by the original number
91 - 851 = -760
-760 ÷ 851 = -0.8930669800235017
-0.8930669800235017 x 100 = -89.31%