I commute year round too, it's fun to compete with some of our other offices. Last year 12 of our offices participated, including ones in Canada and Asia (London is in this year). Our Washington DC office (my office) has had the most riders and highest mileage since we started 3 years ago. We've had almost twice as many riders and mileage as the second place offices. St Louis came in 2nd in mileage last year.

Totaled108 is right, I live far from work so I have the advantage. Last year I logged around 470 miles in May, highest miles but not highest percentage of trips (missed a few days due to work travel). It's great to get people excited about bike commuting, good for your health and good for the environment. I just like riding bikes.