Question: when was the last time the 49ers won the superbowl
[{'answer': '5', 'provenance': [{'wikipedia_id': '27169', 'title': 'San Francisco 49ers', 'start_paragraph_id': 3, 'start_character': 332, 'end_paragraph_id': 3, 'end_character': 333, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]