-90.16% is the change from 671 to 66
Calculation steps:
[( 66 - 671 ) ÷ 671] x 100 = -90.16%
Formula
Percentage change = [(66 - 671) / 671] x 100
Subtract the new number by the original number
66 - 671 = -605
-605 ÷ 671 = -0.9016393442622951
-0.9016393442622951 x 100 = -90.16%