-54.85% is the change from 866 to 391
Calculation steps:
[( 391 - 866 ) ÷ 866] x 100 = -54.85%
Formula
Percentage change = [(391 - 866) / 866] x 100
Subtract the new number by the original number
391 - 866 = -475
-475 ÷ 866 = -0.5484988452655889
-0.5484988452655889 x 100 = -54.85%