-6.36% is the change from 660 to 618
Calculation steps:
[( 618 - 660 ) ÷ 660] x 100 = -6.36%
Formula
Percentage change = [(618 - 660) / 660] x 100
Subtract the new number by the original number
618 - 660 = -42
-42 ÷ 660 = -0.06363636363636363
-0.06363636363636363 x 100 = -6.36%