-6.91% is the change from 666 to 620
Calculation steps:
[( 620 - 666 ) ÷ 666] x 100 = -6.91%
Formula
Percentage change = [(620 - 666) / 666] x 100
Subtract the new number by the original number
620 - 666 = -46
-46 ÷ 666 = -0.06906906906906907
-0.06906906906906907 x 100 = -6.91%