Question: when is the last time the minnesota vikings played in the super bowl
[{'answer': 'the 1970s'}, {'provenance': [{'wikipedia_id': '20134', 'title': 'Minnesota Vikings', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 301, 'bleu_score': 0.7278966288026161, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2632447567385872129}, 'section': 'Section::::Abstract.'}]}]