3.78% is the change from 502 to 521
Calculation steps:
[( 521 - 502 ) ÷ 502] x 100 = 3.78%
Formula
Percentage change = [(521 - 502) / 502] x 100
Subtract the new number by the original number
521 - 502 = 19
19 ÷ 502 = 0.037848605577689244
0.037848605577689244 x 100 = 3.78%