72.9% is the change from 321 to 555
Calculation steps:
[( 555 - 321 ) ÷ 321] x 100 = 72.9%
Formula
Percentage change = [(555 - 321) / 321] x 100
Subtract the new number by the original number
555 - 321 = 234
234 ÷ 321 = 0.7289719626168224
0.7289719626168224 x 100 = 72.9%