I have a dynamic sitemap generated from ASP.NET MVC containing 17000+ urls. The Google webmaster tools dashboard acknowledges that there are 17,023 (as of this moment) urls in that map, but says that only 4 are in the index.

The map was originally submitted over a month ago, and Google appears to be downloading it daily and doesn't complain about format, etc.

A week ago, the webmaster tools page claimed that there were only ~5000 pages (around 16000 were actually there at the time), with ~4000 in the web index.

Can anyone explain this disparity? The map is located at