-99.4% is the change from 665 to 4
Calculation steps:
[( 4 - 665 ) ÷ 665] x 100 = -99.4%
Formula
Percentage change = [(4 - 665) / 665] x 100
Subtract the new number by the original number
4 - 665 = -661
-661 ÷ 665 = -0.9939849624060151
-0.9939849624060151 x 100 = -99.4%