Question: when did nz gst change from 10 to 12.5
[{'answer': '1 July 1989', 'provenance': [{'wikipedia_id': '1628994', 'title': 'Goods and Services Tax (New Zealand)', 'start_paragraph_id': 6, 'start_character': 52, 'end_paragraph_id': 6, 'end_character': 63, 'bleu_score': 1.0, 'section': 'Section::::Background.\n'}]}, {'provenance': [{'wikipedia_id': '1628994', 'title': 'Goods and Services Tax (New Zealand)', 'start_paragraph_id': 6, 'start_character': 0, 'end_paragraph_id': 6, 'end_character': 194, 'bleu_score': 0.9466178497997021, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9491015126347854258}, 'section': 'Section::::Background.\n'}]}]