Question: when did the price of oil start to drop
[{'answer': 'December 23 , 2008', 'provenance': [{'wikipedia_id': '5137675', 'title': 'Price of oil', 'start_paragraph_id': 10, 'start_character': 169, 'end_paragraph_id': 10, 'end_character': 187, 'bleu_score': 1.0, 'section': 'Section::::History.:Price history in the 21st century.\n'}]}, {'provenance': [{'wikipedia_id': '5137675', 'title': 'Price of oil', 'start_paragraph_id': 10, 'start_character': 0, 'end_paragraph_id': 10, 'end_character': 1295, 'bleu_score': 0.842948860652121, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13534689275555854746}, 'section': 'Section::::History.:Price history in the 21st century.\n'}]}]