Question: when did voting age become 18 in uk
[{'answer': '1970', 'provenance': [{'wikipedia_id': '630522', 'title': 'Voting age', 'start_paragraph_id': 2, 'start_character': 118, 'end_paragraph_id': 2, 'end_character': 122, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '630522', 'title': 'Voting age', 'start_paragraph_id': 5, 'start_character': 40, 'end_paragraph_id': 5, 'end_character': 830, 'bleu_score': 0.804758725984923, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15209066256979816466}, 'section': 'Section::::History.\n'}]}]