-50.08% is the change from 621 to 310
Calculation steps:
[( 310 - 621 ) ÷ 621] x 100 = -50.08%
Formula
Percentage change = [(310 - 621) / 621] x 100
Subtract the new number by the original number
310 - 621 = -311
-311 ÷ 621 = -0.500805152979066
-0.500805152979066 x 100 = -50.08%