2.53% is the change from 79 to 81
Calculation steps:
[( 81 - 79 ) ÷ 79] x 100 = 2.53%
Formula
Percentage change = [(81 - 79) / 79] x 100
Subtract the new number by the original number
81 - 79 = 2
2 ÷ 79 = 0.02531645569620253
0.02531645569620253 x 100 = 2.53%