query: SELECT ?item (COUNT(DISTINCT(?person)) AS ?count) ?regioneLabel
  WHERE {
    ?item wdt:P1629 [ wdt:P408 wd:Q107492957 ] .
    OPTIONAL { ?item wdt:P1001 [ wdt:P131* ?regione ] .
    ?regione wdt:P31/wdt:P279* wd:Q16110 . }
    ?item wikibase:directClaim ?itemst .
    ?person ?itemst ?value .
    SERVICE wikibase:label { bd:serviceParam wikibase:language "it". }
  }
  GROUP BY ?item ?count ?regioneLabel