73.44% is the change from 320 to 555
Calculation steps:
[( 555 - 320 ) ÷ 320] x 100 = 73.44%
Formula
Percentage change = [(555 - 320) / 320] x 100
Subtract the new number by the original number
555 - 320 = 235
235 ÷ 320 = 0.734375
0.734375 x 100 = 73.44%