You've done 79 miles in half a tank? Thats 13mpg 
Look a bit further to the right, where it says 324.9miles!

In that case that would be close to 55mpg. I'm assuming that from your user name you have a 1.8t.
In my eyes that leaves 4 options:
1. You forgot to reset your trip counter when you last filled up.
2. You have a diesel and don't realise it.
3. You have the most economical 1.8t ever made.
4. Your just lying.