Are there any surveys anywhere which report on number of projects and/or people using the assorted Free version control systems?
Also interesting is if a similar survey was one over time, to see how things have changed.
Obviously, it's hard to measure this sort of thing completely accurately, but it should still be possible to get reasonable estimates.
Since tags are annoyingly limited to five items, and I didn't want a bias towards/against any of the systems, for search purposes I'll add the following:
bazaar bzr cvs git hg mercurial rcs scm svn subversion vcs scm vcs popularity survey statistics
update: Very few views so far, so I'm cycling the tags to contain the main tags for each software, which might get more eyes on it. If only I could just put all the tags together!