-17.93% is the change from 993 to 815
Calculation steps:
[( 815 - 993 ) ÷ 993] x 100 = -17.93%
Formula
Percentage change = [(815 - 993) / 993] x 100
Subtract the new number by the original number
815 - 993 = -178
-178 ÷ 993 = -0.17925478348439072
-0.17925478348439072 x 100 = -17.93%