-30.39% is the change from 306 to 213
Calculation steps:
[( 213 - 306 ) ÷ 306] x 100 = -30.39%
Formula
Percentage change = [(213 - 306) / 306] x 100
Subtract the new number by the original number
213 - 306 = -93
-93 ÷ 306 = -0.30392156862745096
-0.30392156862745096 x 100 = -30.39%