query: SELECT ?dLabel ?num ?sampleitem with 
  {
    SELECT distinct ?d (count(*) as ?num) (SAMPLE(?item) as ?sampleitem) where
    {
      ?item p:P6216 ?statement .
      ?statement ps:P6216 ?pd .                    # copyright status = public domain
      ?statement pq:P1001 wd:Q30 .
      ?statement pq:P459  ?d .
      VALUES ?pd { wd:Q19652 wd:Q15687061 } 
  } group by ?d } as %i
  where
  {
    include %i
    SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
  }
  order by desc(?num)
  Limit 100