-15.7% is the change from 618 to 521
Calculation steps:
[( 521 - 618 ) ÷ 618] x 100 = -15.7%
Formula
Percentage change = [(521 - 618) / 618] x 100
Subtract the new number by the original number
521 - 618 = -97
-97 ÷ 618 = -0.156957928802589
-0.156957928802589 x 100 = -15.7%