Question: when was the richmond san rafael bridge built
[{'answer': '1956', 'provenance': [{'wikipedia_id': '887273', 'title': 'Richmond–San Rafael Bridge', 'start_paragraph_id': 1, 'start_character': 342, 'end_paragraph_id': 1, 'end_character': 346, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '887273', 'title': 'Richmond–San Rafael Bridge', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 412, 'bleu_score': 0.970795021215021, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3845949391248830594}, 'section': 'Section::::Abstract.'}]}]