21.56% is the change from 320 to 389
Calculation steps:
[( 389 - 320 ) ÷ 320] x 100 = 21.56%
Formula
Percentage change = [(389 - 320) / 320] x 100
Subtract the new number by the original number
389 - 320 = 69
69 ÷ 320 = 0.215625
0.215625 x 100 = 21.56%