-7.31% is the change from 670 to 621
Calculation steps:
[( 621 - 670 ) ÷ 670] x 100 = -7.31%
Formula
Percentage change = [(621 - 670) / 670] x 100
Subtract the new number by the original number
621 - 670 = -49
-49 ÷ 670 = -0.07313432835820896
-0.07313432835820896 x 100 = -7.31%