3.91% is the change from 511 to 531
Calculation steps:
[( 531 - 511 ) ÷ 511] x 100 = 3.91%
Formula
Percentage change = [(531 - 511) / 511] x 100
Subtract the new number by the original number
531 - 511 = 20
20 ÷ 511 = 0.03913894324853229
0.03913894324853229 x 100 = 3.91%