Question: when did iphone 6s come out in us
[{'answer': 'September 25 , 2015', 'provenance': [{'wikipedia_id': '47451953', 'title': 'IPhone 6S', 'start_paragraph_id': 1, 'start_character': 385, 'end_paragraph_id': 1, 'end_character': 404, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '47451953', 'title': 'IPhone 6S', 'start_paragraph_id': 1, 'start_character': 11, 'end_paragraph_id': 1, 'end_character': 479, 'bleu_score': 0.806422586443111, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6189146291353937743}, 'section': 'Section::::Abstract.'}]}]