18.04% is the change from 521 to 615
Calculation steps:
[( 615 - 521 ) ÷ 521] x 100 = 18.04%
Formula
Percentage change = [(615 - 521) / 521] x 100
Subtract the new number by the original number
615 - 521 = 94
94 ÷ 521 = 0.18042226487523993
0.18042226487523993 x 100 = 18.04%