what is the {end time} for {Christian Democratic Union} has {chairperson} as {Helmut Kohl} ?
When Christian Democratic Union ended with its chairperson Helmut Kohl?
SELECT ?value WHERE { wd:Q49762 p:P488 ?s . ?s ps:P488 wd:Q2518 . ?s pq:P582 ?value}
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q49762> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P488> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q2518> .
?statement <http://www.wikidata.org/entity/P582> ?value. 
} 

When did chairperson Helmut Kohl's Christian Democratic Union end?