Question: when did the oil prices start to drop
[{'answer': '2015', 'provenance': [{'wikipedia_id': '5137675', 'title': 'Price of oil', 'start_paragraph_id': 45, 'start_character': 26, 'end_paragraph_id': 45, 'end_character': 30, 'bleu_score': 1.0, 'section': 'Section::::Oil-storage trade (contango).\n'}]}, {'provenance': [{'wikipedia_id': '5137675', 'title': 'Price of oil', 'start_paragraph_id': 72, 'start_character': 0, 'end_paragraph_id': 72, 'end_character': 583, 'bleu_score': 0.923675270965665, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17661469647114373192}, 'section': 'Section::::Hedging as risk management.:2015–16 prices: The lows of January 2016.\n'}]}]