-95.5% is the change from 666 to 30
Calculation steps:
[( 30 - 666 ) ÷ 666] x 100 = -95.5%
Formula
Percentage change = [(30 - 666) / 666] x 100
Subtract the new number by the original number
30 - 666 = -636
-636 ÷ 666 = -0.954954954954955
-0.954954954954955 x 100 = -95.5%