Question: when was the last game of thrones book published
[{'answer': '2011', 'provenance': [{'wikipedia_id': '12301', 'title': 'A Song of Ice and Fire', 'start_paragraph_id': 1, 'start_character': 420, 'end_paragraph_id': 1, 'end_character': 424, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '12301', 'title': 'A Song of Ice and Fire', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 522, 'bleu_score': 0.8290000465200751, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10285243599205926313}, 'section': 'Section::::Abstract.'}]}]