Question: when did they stop allowing smoking on planes
[{'answer': '2000', 'provenance': [{'wikipedia_id': '23415923', 'title': 'Inflight smoking', 'start_paragraph_id': 1, 'start_character': 282, 'end_paragraph_id': 1, 'end_character': 286, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]