You are quite the student of efficiency apudapus. The EPA rules sticker for the Honda Civic Si is 29 hwy, for the mini is 34. I csn see why your average is 28. I do not drive far to work (3.5 miles rt) but I live in Atlanta and have a property in Florida and 2 children (just finished college) in Chicago/Milwaukee. Seems like I do monthly trips to FL and at least annual trips to the midwest. On average I put 20 to 25K per annum. The mini, being directly injected, also tolerates regular fuel. This is ideal for traveling on cruise.