what is the {start time} for {Chongqing} has {twinned administrative body} as {Mpumalanga} ?
When did Chongqing and Mpumalanga become sister cities?
SELECT ?value WHERE { wd:Q11725 p:P190 ?s . ?s ps:P190 wd:Q132410 . ?s pq:P580 ?value}
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q11725> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P190> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q132410> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

At which point in time did Chongqing and Mpumalanga become sister cities?