2.96% is the change from 506 to 521
Calculation steps:
[( 521 - 506 ) ÷ 506] x 100 = 2.96%
Formula
Percentage change = [(521 - 506) / 506] x 100
Subtract the new number by the original number
521 - 506 = 15
15 ÷ 506 = 0.029644268774703556
0.029644268774703556 x 100 = 2.96%