-18.48% is the change from 817 to 666
Calculation steps:
[( 666 - 817 ) ÷ 817] x 100 = -18.48%
Formula
Percentage change = [(666 - 817) / 817] x 100
Subtract the new number by the original number
666 - 817 = -151
-151 ÷ 817 = -0.18482252141982863
-0.18482252141982863 x 100 = -18.48%