27.48% is the change from 644 to 821
Calculation steps:
[( 821 - 644 ) ÷ 644] x 100 = 27.48%
Formula
Percentage change = [(821 - 644) / 644] x 100
Subtract the new number by the original number
821 - 644 = 177
177 ÷ 644 = 0.2748447204968944
0.2748447204968944 x 100 = 27.48%