Question: when was the bone anchored hearing aid invented
[{'answer': '1977', 'provenance': [{'wikipedia_id': '3016334', 'title': 'Bone-anchored hearing aid', 'start_paragraph_id': 45, 'start_character': 3, 'end_paragraph_id': 45, 'end_character': 7, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '3016334', 'title': 'Bone-anchored hearing aid', 'start_paragraph_id': 45, 'start_character': 0, 'end_paragraph_id': 45, 'end_character': 349, 'bleu_score': 0.906944319610487, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8477030410569467047}, 'section': 'Section::::History.\n'}]}]