Question: when did the 6th harry potter book come out
[{'answer': '16 July 2005', 'provenance': [{'wikipedia_id': '2270723', 'title': 'Harry Potter and the Half-Blood Prince', 'start_paragraph_id': 2, 'start_character': 102, 'end_paragraph_id': 2, 'end_character': 114, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]