2.56% is the change from 821 to 842
Calculation steps:
[( 842 - 821 ) ÷ 821] x 100 = 2.56%
Formula
Percentage change = [(842 - 821) / 821] x 100
Subtract the new number by the original number
842 - 821 = 21
21 ÷ 821 = 0.025578562728380026
0.025578562728380026 x 100 = 2.56%