-97.1% is the change from 310 to 9
Calculation steps:
[( 9 - 310 ) ÷ 310] x 100 = -97.1%
Formula
Percentage change = [(9 - 310) / 310] x 100
Subtract the new number by the original number
9 - 310 = -301
-301 ÷ 310 = -0.9709677419354839
-0.9709677419354839 x 100 = -97.1%