Question: when did amazon start charging state sales tax
[{'answer': '2011', 'provenance': [{'wikipedia_id': '31105432', 'title': 'Amazon tax', 'start_paragraph_id': 2, 'start_character': 250, 'end_paragraph_id': 2, 'end_character': 254, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]