Question: when did dental floss come on the market
[{'answer': '1882', 'provenance': [{'wikipedia_id': '487691', 'title': 'Dental floss', 'start_paragraph_id': 5, 'start_character': 447, 'end_paragraph_id': 5, 'end_character': 451, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '487691', 'title': 'Dental floss', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 690, 'bleu_score': 0.9826823455989031, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8753474883637502445}, 'section': 'Section::::History.\n'}]}]