Question: when did nigeria export her first crude oil
[{'answer': 'February 1958', 'provenance': [{'wikipedia_id': '27436052', 'title': 'Oloibiri Oilfield', 'start_paragraph_id': 16, 'start_character': 192, 'end_paragraph_id': 16, 'end_character': 205, 'bleu_score': 1.0, 'section': 'Section::::Production.\n'}]}, {'provenance': [{'wikipedia_id': '27436052', 'title': 'Oloibiri Oilfield', 'start_paragraph_id': 16, 'start_character': 0, 'end_paragraph_id': 16, 'end_character': 349, 'bleu_score': 0.8484204774100531, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12304137362914909632}, 'section': 'Section::::Production.\n'}]}]