-3.21% is the change from 842 to 815
Calculation steps:
[( 815 - 842 ) ÷ 842] x 100 = -3.21%
Formula
Percentage change = [(815 - 842) / 842] x 100
Subtract the new number by the original number
815 - 842 = -27
-27 ÷ 842 = -0.032066508313539195
-0.032066508313539195 x 100 = -3.21%