-50.72% is the change from 621 to 306
Calculation steps:
[( 306 - 621 ) ÷ 621] x 100 = -50.72%
Formula
Percentage change = [(306 - 621) / 621] x 100
Subtract the new number by the original number
306 - 621 = -315
-315 ÷ 621 = -0.5072463768115942
-0.5072463768115942 x 100 = -50.72%