-20.36% is the change from 388 to 309
Calculation steps:
[( 309 - 388 ) ÷ 388] x 100 = -20.36%
Formula
Percentage change = [(309 - 388) / 388] x 100
Subtract the new number by the original number
309 - 388 = -79
-79 ÷ 388 = -0.2036082474226804
-0.2036082474226804 x 100 = -20.36%
Example