The lifetime average is in my fuelly sig -- 56.3. Best tank so far is 60 MPG. I live in a rural area, so almost 100% of my miles are highway of some sort except for the last fraction of a mile or so.
My best 25-mile average is 72 MPG. I got that running the air conditioner and in kind of a hurry to get where I was going.
Even when I have some extra city driving or other things that drag down fuel economy, I'm still beating the EPA highway estimate. Every single tank I've run has been higher than 52 MPG.
I'm ecstatic over the fuel economy with this car. Even when it's bad, it's really good.