query: SELECT ?class ?classLabel (COUNT(DISTINCT ?statement) AS ?count)
  WHERE 
  {
    ?item p:P1923 ?statement.
    ?item wdt:P31 ?class.
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
  }
  GROUP BY ?class ?classLabel
  ORDER BY DESC(?count)