56.7% is the change from 321 to 503
Calculation steps:
[( 503 - 321 ) ÷ 321] x 100 = 56.7%
Formula
Percentage change = [(503 - 321) / 321] x 100
Subtract the new number by the original number
503 - 321 = 182
182 ÷ 321 = 0.5669781931464174
0.5669781931464174 x 100 = 56.7%