Difference in Ideal gas density
 

Hi to all,
I am doing a compressible flow simulation in Fluent.I am using Velocity inlet and static Pressure outlet and Ideal gas (water vapour) as material.
After convergence, I am getting
Inlet (CFD):
Total Pressure = 3.37e6 Pa.
Temperature = 855.2 K
Density = 8.87 Kg/m^3

But in Steam tables for this Pressure and Temperature i am getting

Density = 8.696 Kg/m^3

Why is this difference and how can i correct in my simulation?

Could anybody explain me

Thanks in advance.