Question: when did water fluoridation begin in the uk
[{'answer': '1964', 'provenance': [{'wikipedia_id': '18856018', 'title': 'Fluoridation by country', 'start_paragraph_id': 110, 'start_character': 395, 'end_paragraph_id': 110, 'end_character': 399, 'bleu_score': 1.0, 'section': 'Section::::Europe.:United Kingdom.\n'}]}, {'provenance': [{'wikipedia_id': '18856018', 'title': 'Fluoridation by country', 'start_paragraph_id': 110, 'start_character': 0, 'end_paragraph_id': 110, 'end_character': 408, 'bleu_score': 0.9611463610973231, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16597452436438385402}, 'section': 'Section::::Europe.:United Kingdom.\n'}]}]