28.68% is the change from 638 to 821
Calculation steps:
[( 821 - 638 ) ÷ 638] x 100 = 28.68%
Formula
Percentage change = [(821 - 638) / 638] x 100
Subtract the new number by the original number
821 - 638 = 183
183 ÷ 638 = 0.28683385579937304
0.28683385579937304 x 100 = 28.68%