-9.18% is the change from 991 to 900
Calculation steps:
[( 900 - 991 ) ÷ 991] x 100 = -9.18%
Formula
Percentage change = [(900 - 991) / 991] x 100
Subtract the new number by the original number
900 - 991 = -91
-91 ÷ 991 = -0.09182643794147326
-0.09182643794147326 x 100 = -9.18%