-90.82% is the change from 991 to 91
Calculation steps:
[( 91 - 991 ) ÷ 991] x 100 = -90.82%
Formula
Percentage change = [(91 - 991) / 991] x 100
Subtract the new number by the original number
91 - 991 = -900
-900 ÷ 991 = -0.9081735620585267
-0.9081735620585267 x 100 = -90.82%