-31.7% is the change from 306 to 209
Calculation steps:
[( 209 - 306 ) ÷ 306] x 100 = -31.7%
Formula
Percentage change = [(209 - 306) / 306] x 100
Subtract the new number by the original number
209 - 306 = -97
-97 ÷ 306 = -0.31699346405228757
-0.31699346405228757 x 100 = -31.7%