Question: when did they start putting fluoride in toothpaste
[{'answer': 'the 1890s', 'provenance': [{'wikipedia_id': '147735', 'title': 'Toothpaste', 'start_paragraph_id': 64, 'start_character': 43, 'end_paragraph_id': 64, 'end_character': 52, 'bleu_score': 1.0, 'section': 'Section::::History.:Modern toothpaste.\n'}]}, {'provenance': [{'wikipedia_id': '147735', 'title': 'Toothpaste', 'start_paragraph_id': 64, 'start_character': 0, 'end_paragraph_id': 64, 'end_character': 1067, 'bleu_score': 0.9878413801697931, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16002245668523144183}, 'section': 'Section::::History.:Modern toothpaste.\n'}]}]