Question: when was the microwave introduced to the public
[{'answer': '1946', 'provenance': [{'wikipedia_id': '58017', 'title': 'Microwave oven', 'start_paragraph_id': 2, 'start_character': 343, 'end_paragraph_id': 2, 'end_character': 347, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '58017', 'title': 'Microwave oven', 'start_paragraph_id': 2, 'start_character': 40, 'end_paragraph_id': 2, 'end_character': 926, 'bleu_score': 0.772906974894024, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1617790049386094818}, 'section': 'Section::::Abstract.'}]}]