Question: when did new zealand change from miles to kilometres
[{'answer': '1975', 'provenance': [{'wikipedia_id': '28586878', 'title': 'Speed limits in New Zealand', 'start_paragraph_id': 11, 'start_character': 146, 'end_paragraph_id': 11, 'end_character': 150, 'bleu_score': 1.0, 'section': 'Section::::Current speed limits.\n'}]}]