-18.73% is the change from 817 to 664
Calculation steps:
[( 664 - 817 ) ÷ 817] x 100 = -18.73%
Formula
Percentage change = [(664 - 817) / 817] x 100
Subtract the new number by the original number
664 - 817 = -153
-153 ÷ 817 = -0.18727050183598531
-0.18727050183598531 x 100 = -18.73%