query: SELECT ?parent ?parentLabel ?count
  WHERE
  {
    {
      SELECT ?parent (COUNT(?child) AS ?count)
      WHERE
      {
        ?parent wdt:P40 ?child.
      }
      GROUP BY ?parent
      ORDER BY DESC(?count)
      LIMIT 10
    }
    SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
  }
  ORDER BY DESC(?count)
  LIMIT 10