Re: Only 10%?
Everyone knows the official figures are unobtainable
That's true - no one every gets the quoted figure. But the point of the official figure, oddly enough, is not to say what the actual consumption is. The intention is that it's used purely as a relative comparator, not an absolute, so that you know that a car with an official consumption figure of 70 mpg will be more efficient than one with a 60 mpg figure, and not that either will actually deliver the quoted consumption figure
The problem is that it has a unit associated with it, so it becomes measurable in the real world. If it was simply a grading, say from A to Z, with A being really good and Z being really bad, people wouldn't complain. That grading comes with its own issues, though, such as how do you grade a new car in a few years time that beats the current 'A' grade?