21.11% is the change from 521 to 631
Calculation steps:
[( 631 - 521 ) ÷ 521] x 100 = 21.11%
Formula
Percentage change = [(631 - 521) / 521] x 100
Subtract the new number by the original number
631 - 521 = 110
110 ÷ 521 = 0.21113243761996162
0.21113243761996162 x 100 = 21.11%