How many {occupation} are to/by {percussion instrument} ?
Percussion instruments are occupied by how many people?
how many occupy the percussion intruments?
SELECT ( COUNT ( ?r ) AS ?c ) { ?r property:occupation resource:percussion_instrument }
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/P106> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q133163 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P106 wd:Q133163 }
6