-5.31% is the change from 866 to 820
Calculation steps:
[( 820 - 866 ) ÷ 866] x 100 = -5.31%
Formula
Percentage change = [(820 - 866) / 866] x 100
Subtract the new number by the original number
820 - 866 = -46
-46 ÷ 866 = -0.053117782909930716
-0.053117782909930716 x 100 = -5.31%