-99.1% is the change from 667 to 6
Calculation steps:
[( 6 - 667 ) ÷ 667] x 100 = -99.1%
Formula
Percentage change = [(6 - 667) / 667] x 100
Subtract the new number by the original number
6 - 667 = -661
-661 ÷ 667 = -0.9910044977511244
-0.9910044977511244 x 100 = -99.1%