I don't have a fixed commute as such (I work more or less from home but usually make several trips during the day). I think that it is fair to say that I spent an average of 1 hour with my buttocks on my bike seat every day (between 45 min and 1h30 on most weekdays).

I don't have one of these computer thing so to translate that into mileage is a guess. how fast does one go at a steady pace (but without racing) on a touring bike? 15m ph? 20?