3.78% is the change from 820 to 851
Calculation steps:
[( 851 - 820 ) ÷ 820] x 100 = 3.78%
Formula
Percentage change = [(851 - 820) / 820] x 100
Subtract the new number by the original number
851 - 820 = 31
31 ÷ 820 = 0.03780487804878049
0.03780487804878049 x 100 = 3.78%