static function insertCount($d, $n)
 {
     $suc = new Sitemap_user_count();
     $suc->registration_date = DB_DataObject_Cast::date($d);
     $suc->user_count = $n;
     $suc->created = common_sql_now();
     $suc->modified = $suc->created;
     if (!$suc->insert()) {
         common_log(LOG_WARNING, "Could not save user counts for '{$d}'");
     }
 }