Question: when was the first king size bed made
[{'answer': 'In the mid-1950s', 'provenance': [{'wikipedia_id': '951407', 'title': 'Bed', 'start_paragraph_id': 27, 'start_character': 0, 'end_paragraph_id': 27, 'end_character': 16, 'bleu_score': 1.0, 'section': 'Section::::Bed sizes.\n'}]}, {'provenance': [{'wikipedia_id': '951407', 'title': 'Bed', 'start_paragraph_id': 27, 'start_character': 0, 'end_paragraph_id': 27, 'end_character': 677, 'bleu_score': 0.7901422622430051, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13512399671425626435}, 'section': 'Section::::Bed sizes.\n'}]}]