-3.12% is the change from 866 to 839
Calculation steps:
[( 839 - 866 ) ÷ 866] x 100 = -3.12%
Formula
Percentage change = [(839 - 866) / 866] x 100
Subtract the new number by the original number
839 - 866 = -27
-27 ÷ 866 = -0.03117782909930716
-0.03117782909930716 x 100 = -3.12%