As I am sure you know, fuel economy depends on a variety of factors: temperature, driving style, tire pressure, gas type, etc.

That being said, I have easily attained 50 mpg (plus or minus 2 mpg) since purchasing the car 6000 miles ago and I don't drive much differently than I used to. Interestingly, even in the rain and other difficult highway driving conditions (traffic and hills), the worst FE I have ever received was around 44 mpg over the course of a trip.

Something doesn't seem right to me about your situation - I couldn't get below 40 mpg if I tried.

I wonder if anyone else will have some insight into this problem.