2.53% is the change from 830 to 851
Calculation steps:
[( 851 - 830 ) ÷ 830] x 100 = 2.53%
Formula
Percentage change = [(851 - 830) / 830] x 100
Subtract the new number by the original number
851 - 830 = 21
21 ÷ 830 = 0.02530120481927711
0.02530120481927711 x 100 = 2.53%