11.55% is the change from 251 to 280
Calculation steps:
[( 280 - 251 ) ÷ 251] x 100 = 11.55%
Formula
Percentage change = [(280 - 251) / 251] x 100
Subtract the new number by the original number
280 - 251 = 29
29 ÷ 251 = 0.11553784860557768
0.11553784860557768 x 100 = 11.55%