Maybe it already does but it's unclear (see example URL).
Important because the column determines the order in which languages are shown (at least for most projects) and monthly stats are extremely fluctuating (see e.g. http://stats.wikimedia.org/wiktionary/EN/TablesPageViewsMonthly.htm).
Version: unspecified
Severity: enhancement
URL: http://stats.wikimedia.org/wiktionary/EN/Sitemap.htm
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=46203