-30.78% is the change from 991 to 686
Calculation steps:
[( 686 - 991 ) ÷ 991] x 100 = -30.78%
Formula
Percentage change = [(686 - 991) / 991] x 100
Subtract the new number by the original number
686 - 991 = -305
-305 ÷ 991 = -0.3077699293642785
-0.3077699293642785 x 100 = -30.78%