-40.3% is the change from 866 to 517
Calculation steps:
[( 517 - 866 ) ÷ 866] x 100 = -40.3%
Formula
Percentage change = [(517 - 866) / 866] x 100
Subtract the new number by the original number
517 - 866 = -349
-349 ÷ 866 = -0.40300230946882215
-0.40300230946882215 x 100 = -40.3%