What is {visitors per year} of {Yellowstone National Park} that is {point in time} is {2015-0-0} ?
In 2015 what was the attendance at Yellowstone National Park?
How many people visited Yellowstone National Park in 2015?
SELECT ?p WHERE { resource:Yellowstone_National_Park property:visitors_per_year ?m . ?m property:visitors_per_year ?p . ?m property:point_in_time ?q . FILTER ( CONTAINS ( YEAR ( ?q ) , '2015' ) ) }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q351> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1174> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
?statement <http://www.wikidata.org/entity/P585> <2015-0-0>
} 

SELECT ?obj WHERE { wd:Q351 p:P1174 ?s . ?s ps:P1174 ?obj . ?s pq:P585 ?x filter(contains(YEAR(?x),'2015')) }