It all depends how you drive and if you use cruise control. For example, i went on a spot of motorway driving NEVER exceeding 80mph and these twere the figures i got. See pics below: -
Bear in mind i had already done: -
And to top it all i drive an automatic 2.2 which is a bit more heavier on fuel. I do keep it regularly serviced and where possible i make sure tracking is ok too (less rolling resistance)