Not quite sure what you mean, to be honest?
Where would you like to have filters? You can go through the tabs to get more detailed info.
The D/T matrix can be toggled to other cache types by clicking on the upper right corner (default: All Types)
Are you sure, you are talking about the Project-GC statistics and not geocaching.com?
Edit: The "where" is now clarified, I did not get the initial problem.
On the linked page, only the country filter is possible at the moment, as stated by Abused.
Since I cannot productively help, I'll convert it into a comment.
