query: #Unique value constraint report for P1447: report by value
  #by Jura1 2016-05-03
  SELECT 
  	?value ?valueLabel 
  	(COUNT(DISTINCT ?item) as ?ct) 
  	(GROUP_CONCAT(DISTINCT(strafter(str(?item), "/entity/"));separator=", ") as ?items)
  	(GROUP_CONCAT(DISTINCT(?itemLabel);separator=", ") as ?itemLabels)
  WHERE
  {
  	?value ^wdt:P1447 ?item .
  	SERVICE wikibase:label { bd:serviceParam wikibase:language "lv,en,nb,es,nl,sv,pl,de,fr,pt,fi,bg,uk,ru" . ?item rdfs:label ?itemLabel . ?value rdfs:label ?valueLabel } .
  }
  GROUP BY ?value ?valueLabel
  HAVING (?ct>1)
  ORDER BY DESC(?ct)
  LIMIT 500