Question: when did england last win 6 nations grand slam
[{'answer': '2016', 'provenance': [{'wikipedia_id': '3933705', 'title': 'Grand Slam (rugby union)', 'start_paragraph_id': 7, 'start_character': 98, 'end_paragraph_id': 7, 'end_character': 102, 'bleu_score': 1.0, 'section': 'Section::::Five and Six Nations Grand Slams.\n'}]}]