Question: when did ben nevis win the grand national
[{'answer': '1980', 'provenance': [{'wikipedia_id': '51273953', 'title': 'Ben Nevis (horse)', 'start_paragraph_id': 7, 'start_character': 139, 'end_paragraph_id': 7, 'end_character': 143, 'bleu_score': 1.0, 'section': 'Section::::Return to England.\n'}]}, {'provenance': [{'wikipedia_id': '51273953', 'title': 'Ben Nevis (horse)', 'start_paragraph_id': 7, 'start_character': 0, 'end_paragraph_id': 7, 'end_character': 657, 'bleu_score': 0.9577362712813341, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11437419355918922134}, 'section': 'Section::::Return to England.\n'}]}]