The City of Copenhagen recently released their Bicycle Account 2010, a comprehensive look at the state of Cycling within the City. The report is based on survey data as well as other quantitative measures. What is most notable about this data summary is how far-reaching it is in scope. I don’t think there are any US cities doing anything similar.
Since I don’t know much about how the statistics in the report were calculated or how the data is collected, it’s hard to draw any conclusions from this data summary. But it’s worth checking out.