2.51% is the change from 399 to 409
Calculation steps:
[( 409 - 399 ) ÷ 399] x 100 = 2.51%
Formula
Percentage change = [(409 - 399) / 399] x 100
Subtract the new number by the original number
409 - 399 = 10
10 ÷ 399 = 0.02506265664160401
0.02506265664160401 x 100 = 2.51%