Dear it is too low, and not the correct way of checking fuel average.
How can one check fuel average of 2000~2400 cc vehicle, by just driving it around 5 Kms?
In your particular case, I would suggest to check it from full tank to full tank basis, or at least, driving for at least 300~400 Kms.
Full the tank. Take your car on long route, or, where you can drive it continuously with peace of mind. Again refuel. Check the distance covered and fuel consumed, and calculate the fuel efficiency.