-4.23% is the change from 851 to 815
Calculation steps:
[( 815 - 851 ) ÷ 851] x 100 = -4.23%
Formula
Percentage change = [(815 - 851) / 851] x 100
Subtract the new number by the original number
815 - 851 = -36
-36 ÷ 851 = -0.04230317273795535
-0.04230317273795535 x 100 = -4.23%