5.26% is the change from 399 to 420
Calculation steps:
[( 420 - 399 ) ÷ 399] x 100 = 5.26%
Formula
Percentage change = [(420 - 399) / 399] x 100
Subtract the new number by the original number
420 - 399 = 21
21 ÷ 399 = 0.05263157894736842
0.05263157894736842 x 100 = 5.26%