-89% is the change from 991 to 109
Calculation steps:
[( 109 - 991 ) ÷ 991] x 100 = -89%
Formula
Percentage change = [(109 - 991) / 991] x 100
Subtract the new number by the original number
109 - 991 = -882
-882 ÷ 991 = -0.8900100908173562
-0.8900100908173562 x 100 = -89%