MPG really depends on driving style. Two things I've noticed:
1. If your main concern is mpg, ALWAYS keep it on eco-mode/default drive mode. Sport-mode not only takes off eco-mode, but also tends to hold lower gears/higher revs unnecessarily.
2. Give the car another 500-1000miles. I averaged about 17-18mpg for my first 1000miles. Now I have 4900miles and average 21-22mpg.
(these numbers are average of 50/50 city/highway)