5.51% is the change from 399 to 421
Calculation steps:
[( 421 - 399 ) ÷ 399] x 100 = 5.51%
Formula
Percentage change = [(421 - 399) / 399] x 100
Subtract the new number by the original number
421 - 399 = 22
22 ÷ 399 = 0.05513784461152882
0.05513784461152882 x 100 = 5.51%