-1.73% is the change from 866 to 851
Calculation steps:
[( 851 - 866 ) ÷ 866] x 100 = -1.73%
Formula
Percentage change = [(851 - 866) / 866] x 100
Subtract the new number by the original number
851 - 866 = -15
-15 ÷ 866 = -0.017321016166281754
-0.017321016166281754 x 100 = -1.73%