521.21% is the change from 99 to 615
Calculation steps:
[( 615 - 99 ) ÷ 99] x 100 = 521.21%
Formula
Percentage change = [(615 - 99) / 99] x 100
Subtract the new number by the original number
615 - 99 = 516
516 ÷ 99 = 5.212121212121212
5.212121212121212 x 100 = 521.21%