Check this link http://www.honestjohn.co.uk/road_tests/?id=42

Here you will see a roadtest where a heavy footed driver averaged 14 MPG and then the other road tester managed 24Mpg but driving like a wimp!!The car is the sports packaged version with the 19" wheels so it is expected to consume more than an X5 on 17s or 18s.
In your picture,I see 33.2 Mpg and 24.1 Mpg with an average speed showing
of 45.7 km/h(28.5Mph).Still I am glad that you are happy with consumption of your X5.The best I have seen on mine ,not exceeding any speed limits was 28 Mpg!(I have the 20"s btw)