27.73% is the change from 642 to 820
Calculation steps:
[( 820 - 642 ) ÷ 642] x 100 = 27.73%
Formula
Percentage change = [(820 - 642) / 642] x 100
Subtract the new number by the original number
820 - 642 = 178
178 ÷ 642 = 0.2772585669781931
0.2772585669781931 x 100 = 27.73%