-16.88% is the change from 800 to 665
Calculation steps:
[( 665 - 800 ) ÷ 800] x 100 = -16.88%
Formula
Percentage change = [(665 - 800) / 800] x 100
Subtract the new number by the original number
665 - 800 = -135
-135 ÷ 800 = -0.16875
-0.16875 x 100 = -16.88%