What’s the deal with my AU's fuel consumption?

[peterljohnson55]

I really don’t think I am getting reasonable fuel consumption, so perhaps some can give me advice on what I should do.

VEHICLE
3/2001 Ford Fairmont Ghia AU2, Tickford 6 cyl, 4L VCT.

HISTORY
Engine has done 153,000 kms. Engine runs well.
At 139,000 new leads, plugs and coil pack were fitted.
Oil changed every 8000kms about.

THIS YEAR
The following figures are very accurate….
Have travelled 3,200kms: of which 2200kms is city and suburban; and 1000kms is Freeway driving, where I normally sit on 100-110kph.
My driving style is relaxed and not aggressive.

FUEL CONSUMPTION:
450 litres of E10 for those 3,200kms
= 14.06 L/100kms (69% is city and suburban, 31% freeway).
To me this seems very high, especially given freeway component, but I cannot figure a reason for it being so high.
I think 10 or 11L/100km would be more reasonable.

I AM LOOKING FOR IDEAS ON …
- why the consumption is very high?
- any economical ways to improve consumption ?

Your interest and advice is appreciated, with thanks.