In September 2011 the League of American Bicyclists released two tables of bicycle commute data, the 2010 bicycle commute estimates for 375 American cities and a 10 year comparison of the 70 largest cities. The data shows that more than half of one percent of American workers use a bicycle as their primary mode of transportation to work, close to 40 percent growth since 2000.

For the third year in a row, data released by the US Census Bureau’s American Community Survey show that more than half of one percent of American workers use a bicycle as their primary mode of transportation to work.
See the bike commuter estimates for the 375 cities for which the ACS released bike commuter numbers.
A look at the country’s 70 largest cities shows that the communities that have done the most to promote bicycling through engineering, education, encouragement, enforcement, and evaluation – determined by the League’s Bicycle Friendly America program – have seen greater increases in bike commuting over the past decade than non-Bicycle Friendly Communities.
Since 2005, the 38 Bicycle Friendly Communities among the 70 largest cities saw a 95 percent average increase in bicycle commuting. In contrast, the 32 non-Bicycle Friendly Communities (among the largest 70) grew 46 percent. Since 2000, large Bicycle Friendly Communities grew 78 percent, compared to 55 percent for large non-BFCs.