Interesting. I started bike-commuting first workday of 2013, and have been 'full-time' ever since, which includes occasional driving days for required errands, and a couple months out for a couple injuries. I tracked my commuting days over at the bikejournal.com commuter cycling century challenge for 2-3 years, but got tired of it. I never quite made 200 days, but was in the 170-180 days/year range.