-88.63% is the change from 800 to 91
Calculation steps:
[( 91 - 800 ) ÷ 800] x 100 = -88.63%
Formula
Percentage change = [(91 - 800) / 800] x 100
Subtract the new number by the original number
91 - 800 = -709
-709 ÷ 800 = -0.88625
-0.88625 x 100 = -88.63%