How many {choreographer} are to/by {George Balanchine} ?
How much choreography did George Balanchine do in his lifetime?
How many choreographs are by George Balanchine?
SELECT ( COUNT ( ?u ) AS ?v ) { ?u property:choreographer resource:George_Balanchine }
SELECT (COUNT(?sub) AS ?subs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> ?sub .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1809> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q310184 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P1809 wd:Q310184 }
70