23.75% is the change from 80 to 99
Calculation steps:
[( 99 - 80 ) ÷ 80] x 100 = 23.75%
Formula
Percentage change = [(99 - 80) / 80] x 100
Subtract the new number by the original number
99 - 80 = 19
19 ÷ 80 = 0.2375
0.2375 x 100 = 23.75%
Example