-9.89% is the change from 91 to 82
Calculation steps:
[( 82 - 91 ) ÷ 91] x 100 = -9.89%
Formula
Percentage change = [(82 - 91) / 91] x 100
Subtract the new number by the original number
82 - 91 = -9
-9 ÷ 91 = -0.0989010989010989
-0.0989010989010989 x 100 = -9.89%