What is {number of out of school children} of {Samoa} that is {point in time} is {1999-1-1} ?
How many schoolchildren were there in Samoa on January 1, 1991?
SELECT ?obj WHERE { wd:Q683 p:P2573 ?s . ?s ps:P2573 ?obj . ?s pq:P585 ?x filter(contains(YEAR(?x),'1999')) }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q683> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P2573> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
?statement <http://www.wikidata.org/entity/P585> <1999-1-1>
} 

On January 1, 1991 in Samoa how many schoolchildren were there?