-0.15% is the change from 666 to 665
Calculation steps:
[( 665 - 666 ) ÷ 666] x 100 = -0.15%
Formula
Percentage change = [(665 - 666) / 666] x 100
Subtract the new number by the original number
665 - 666 = -1
-1 ÷ 666 = -0.0015015015015015015
-0.0015015015015015015 x 100 = -0.15%