Question: when did north korea join the united nations
[{'answer': '17 September 1991', 'provenance': [{'wikipedia_id': '39621567', 'title': 'Korea and the United Nations', 'start_paragraph_id': 1, 'start_character': 369, 'end_paragraph_id': 1, 'end_character': 386, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '39621567', 'title': 'Korea and the United Nations', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 449, 'bleu_score': 0.944041853942402, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5772848661056403618}, 'section': 'Section::::Abstract.'}]}]