I commute by bike every day I work - normally 5 days a week (but lately 6-7). There are only 3 days per year that I won't commute by bike: The 2 days that I need to have my car and truck inspected and the one day I have to go to a neighboring city for training.
About the poll: There were a few times when I forgot something at work and had to go back for it. Do I count 2 days or just one?