Currently the Translate extension provides two types of interesting statistics:
* % of completion of all pages in a specific language, including "All message groups together"
* % of completion of all languages in a specific page, including "All languages together"
However, what is missing is a table where you can see the % of translation of all message groups in all languages.
This is usually a good incentive for translators: "We are 4th in the ranking!", "Oh look, we just passed Greek!", "Careful, at this pace Polish will surpass us in a week..."
Less emotionally, :) it is also a good indicator for translators and site admins of the strongest/weakest languages in a wiki. Now it takes a lot of memory or browsing page by page.