Question: when did the us start celebrating the 4th of july
[{'answer': '1777', 'provenance': [{'wikipedia_id': '781729', 'title': 'Independence Day (United States)', 'start_paragraph_id': 9, 'start_character': 15, 'end_paragraph_id': 9, 'end_character': 19, 'bleu_score': 1.0, 'section': 'Section::::Observance.\n'}]}, {'provenance': [{'wikipedia_id': '781729', 'title': 'Independence Day (United States)', 'start_paragraph_id': 9, 'start_character': 19, 'end_paragraph_id': 9, 'end_character': 489, 'bleu_score': 0.741029777086833, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15763006456435253811}, 'section': 'Section::::Observance.\n'}]}]