John Lawrence has posted dogfood usage stats in the past.  I took a look at the changeset "milestones" today.  The rate of changesets being created has certainly increased as more users have been added to the system.

To get the latest changeset, you can run h changeset /latest or h changeset /latest /i if you don't want the gui.  For any given changeset, you can specify the number, such as h changeset 4000 /i.  You could also use the history command, h history $/ /r /i, to see them all (use /stopafter to limit the number of changesets returned by history, such as /stopafter:10 to see only the last 10 changesets).

Latest at the moment is changeset 5771
Changeset 5000 was checked in on June 29
Changeset 4000 was checked in on June 13
Changeset 3000 was checked in on May 20
Changeset 2000 was checked in on April 26
Changeset 1000 was checked in on March 15
Changeset 1 (creation of the server - that upgrade started with a fresh server installation) was checked in on December 10, 2004