what is the {point in time} for {North Carolina} has {population} as {3.17028e+06} ?
When did North Carolina have a population of 3,170,280?
SELECT ?value WHERE { wd:Q1454 p:P1082 ?s . ?s ps:P1082 ?x filter(contains(?x,'3.17028e+06')) . ?s pq:P585 ?value}
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q1454> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1082> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <3.17028e+06> .
?statement <http://www.wikidata.org/entity/P585> ?value. 
} 

At which time did North Carolina's population reach 3,170,280?