Question: From how many countries have people participated in the Excelsior Stakes?
SPARQL query: SELECT DISTINCT COUNT(?uri) WHERE { ?x <http://dbpedia.org/property/race> <http://dbpedia.org/resource/Excelsior_Stakes> . ?x <http://dbpedia.org/ontology/birthPlace> ?uri  . }
Answer: There are [63] birthplaces of the people who participated in the Excelsior Stakes race.