-52.34% is the change from 642 to 306
Calculation steps:
[( 306 - 642 ) ÷ 642] x 100 = -52.34%
Formula
Percentage change = [(306 - 642) / 642] x 100
Subtract the new number by the original number
306 - 642 = -336
-336 ÷ 642 = -0.5233644859813084
-0.5233644859813084 x 100 = -52.34%