Question: when did uk start selling petrol in litres
[{'answer': '1976', 'provenance': [{'wikipedia_id': '2732151', 'title': 'Metrication in the United Kingdom', 'start_paragraph_id': 57, 'start_character': 439, 'end_paragraph_id': 57, 'end_character': 443, 'bleu_score': 1.0, 'section': 'Section::::1965 onwards.:Education.\n'}]}]