Question: when was fen phen taken off the market
[{'answer': 'September 1997', 'provenance': [{'wikipedia_id': '590951', 'title': 'Fenfluramine/phentermine', 'start_paragraph_id': 6, 'start_character': 209, 'end_paragraph_id': 6, 'end_character': 223, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '590951', 'title': 'Fenfluramine/phentermine', 'start_paragraph_id': 6, 'start_character': 0, 'end_paragraph_id': 6, 'end_character': 223, 'bleu_score': 0.83851300471302, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1348503856464653161}, 'section': 'Section::::History.\n'}]}]