Currently we can't count items in Namespace Txikipedia, as we can only do it via a category. But articles in category count also counts categories in categories, templates and so on. Would it be possible to enable article count per namespace?
You probably can count them with a SQL query on quarry.wmflabs.org:
SELECT COUNT(*) FROM page WHERE page_namespace = 104 AND page_is_redirect = 0;
But if you wish something more like MediaWiki does, you can filter the pages to include only those with one link (ie you don't count orphaned page):
SELECT COUNT(DISTINCT(page_id)) FROM pagelinks INNER JOIN page ON pl_from = page_id WHERE page_namespace = 104 AND page_is_redirect = 0;
Quarry let you export the resultset table in wikicode, that you can copy/paste to a wikipage. Note that it's not yet possible to automatically re-execute a quarry periodically (T101835).
I think that we can close this task as invalid, since nothing can be done in the Wikimedia-Site-requests project.