7.95% is the change from 390 to 421
Calculation steps:
[( 421 - 390 ) ÷ 390] x 100 = 7.95%
Formula
Percentage change = [(421 - 390) / 390] x 100
Subtract the new number by the original number
421 - 390 = 31
31 ÷ 390 = 0.07948717948717948
0.07948717948717948 x 100 = 7.95%