-3.55% is the change from 845 to 815
Calculation steps:
[( 815 - 845 ) ÷ 845] x 100 = -3.55%
Formula
Percentage change = [(815 - 845) / 845] x 100
Subtract the new number by the original number
815 - 845 = -30
-30 ÷ 845 = -0.03550295857988166
-0.03550295857988166 x 100 = -3.55%