-50.65% is the change from 620 to 306
Calculation steps:
[( 306 - 620 ) ÷ 620] x 100 = -50.65%
Formula
Percentage change = [(306 - 620) / 620] x 100
Subtract the new number by the original number
306 - 620 = -314
-314 ÷ 620 = -0.5064516129032258
-0.5064516129032258 x 100 = -50.65%