How many companies have manufactured the rockets launched from the Cape Canaveral Air Force Station?
SELECT DISTINCT COUNT(?uri) WHERE { ?x <http://dbpedia.org/ontology/launchSite> <http://dbpedia.org/resource/Cape_Canaveral_Air_Force_Station> . ?x <http://dbpedia.org/ontology/manufacturer> ?uri  . }
Cape_Canaveral_Air_Force_Station