I don't have either an OTIS or EVIC (would like one though) but I have been keeping track of my mileage since day one with this car. I've got a mix of highway and city, mostly highway back and forth to work. Roughly 75-80% highway. I have a spreadsheet at home with over 2 years of mileage so when I get home I can give you an average from May 2004 thru the last time I filled up. And that's from 48k miles when I bought it thru recently at whatever miles I'm at now in my sig, over 85K. So I've got good data, and if memory serves me, I think my average is in between 23 and 24, a little closer to 23. I'll check that when I get home. I've seen it as high as 28-29 (really long highway trip) and as low as 17 (really cold stretch in winter like -20F).