Question: when was the carbon tax introduced in australia
[{'answer': 'in 2011', 'provenance': [{'wikipedia_id': '36133183', 'title': 'Carbon pricing in Australia', 'start_paragraph_id': 1, 'start_character': 135, 'end_paragraph_id': 1, 'end_character': 142, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '36133183', 'title': 'Carbon pricing in Australia', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 655, 'bleu_score': 0.9823771291847391, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15821849722756074817}, 'section': 'Section::::Abstract.'}]}]