Question: when was the first supermarket opened in usa
[{'answer': '4 August 1930', 'provenance': [{'wikipedia_id': '51862', 'title': 'Supermarket', 'start_paragraph_id': 12, 'start_character': 131, 'end_paragraph_id': 12, 'end_character': 144, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '51862', 'title': 'Supermarket', 'start_paragraph_id': 12, 'start_character': 0, 'end_paragraph_id': 12, 'end_character': 610, 'bleu_score': 0.8957448584030551, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17208188570903632462}, 'section': 'Section::::History.\n'}]}]