28.48% is the change from 639 to 821
Calculation steps:
[( 821 - 639 ) ÷ 639] x 100 = 28.48%
Formula
Percentage change = [(821 - 639) / 639] x 100
Subtract the new number by the original number
821 - 639 = 182
182 ÷ 639 = 0.28482003129890454
0.28482003129890454 x 100 = 28.48%