Question: when did hpv vaccine became available in us
[{'answer': '2006', 'provenance': [{'wikipedia_id': '3304705', 'title': 'HPV vaccine', 'start_paragraph_id': 4, 'start_character': 42, 'end_paragraph_id': 4, 'end_character': 46, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '3304705', 'title': 'HPV vaccine', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 456, 'bleu_score': 0.944475589384524, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 753267755321264007}, 'section': 'Section::::Abstract.'}]}]