First tank of gas guzzled on the S50 m3... 18.99mpg

So I got my first tank of gas all used up, and the car gets (so far) 18.99 miles per gallon.  Not bad considering how I have been driving.  I have a feeling I would see about 24 or so if driving 75mph non stop on a freeway.  I expect to see below 10 on the track!