-50.49% is the change from 618 to 306
Calculation steps:
[( 306 - 618 ) ÷ 618] x 100 = -50.49%
Formula
Percentage change = [(306 - 618) / 618] x 100
Subtract the new number by the original number
306 - 618 = -312
-312 ÷ 618 = -0.5048543689320388
-0.5048543689320388 x 100 = -50.49%