-21.13% is the change from 388 to 306
Calculation steps:
[( 306 - 388 ) ÷ 388] x 100 = -21.13%
Formula
Percentage change = [(306 - 388) / 388] x 100
Subtract the new number by the original number
306 - 388 = -82
-82 ÷ 388 = -0.211340206185567
-0.211340206185567 x 100 = -21.13%