Question: when did service tax rate change to 15
[{'answer': '1 June 2016', 'provenance': [{'wikipedia_id': '18040203', 'title': 'Service Tax', 'start_paragraph_id': 1, 'start_character': 860, 'end_paragraph_id': 1, 'end_character': 871, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '18040203', 'title': 'Service Tax', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 1188, 'bleu_score': 0.904999176343186, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15322129268551080882}, 'section': 'Section::::Abstract.'}]}]