20.54% is the change from 331 to 399
Calculation steps:
[( 399 - 331 ) ÷ 331] x 100 = 20.54%
Formula
Percentage change = [(399 - 331) / 331] x 100
Subtract the new number by the original number
399 - 331 = 68
68 ÷ 331 = 0.2054380664652568
0.2054380664652568 x 100 = 20.54%