37.84% is the change from 399 to 550
Calculation steps:
[( 550 - 399 ) ÷ 399] x 100 = 37.84%
Formula
Percentage change = [(550 - 399) / 399] x 100
Subtract the new number by the original number
550 - 399 = 151
151 ÷ 399 = 0.37844611528822053
0.37844611528822053 x 100 = 37.84%