The statistics for OpenOffice.org (probably as well as those for projects working similar) have a serious flaw: commits on CVS branches are not counted as contribution. OOo development takes place on CVS branches of selected modules, so-called Child Workspaces (CWS), that are integrated to HEAD when a feature or fix is ready and QA'ed. So the main contributors listed on http://www.ohloh.net/projects/29/analyses/latest/contributors are actually the release engineers who merge the CWS branches to HEAD, or contributors committing HTML of the web sites to HEAD, but not the actual code contributors. It looks as if developers ceased to contribute code in 2003, back when we introduced the CWS handling..
Regards Eike