31.87% is the change from 251 to 331
Calculation steps:
[( 331 - 251 ) ÷ 251] x 100 = 31.87%
Formula
Percentage change = [(331 - 251) / 251] x 100
Subtract the new number by the original number
331 - 251 = 80
80 ÷ 251 = 0.3187250996015936
0.3187250996015936 x 100 = 31.87%