A great topic! These are mine observations with F20 116i, 50.000 km:
7.0±0.5l/100km (ca 33 MPG) - economy driving
8.0±0.5l/100km (ca 29 MPG) - normal driving
9.0±0.5l/100km (ca 26 MPG) - now, that's my car!
I don't like to think too much about the economy while driving and it shows 8.5l/100 km (ca 27 MPG). Not bad considering I do have fun. I drive 25% city and 75% outside, always on Sport unless the winter conditions force me to use Comfort or Eco Pro (which
makes me a sad panda).