Question: when did the british army got final defeat against the united state of america
[{'answer': 'October 17 , 1781', 'provenance': [{'wikipedia_id': '771', 'title': 'American Revolutionary War', 'start_paragraph_id': 77, 'start_character': 1410, 'end_paragraph_id': 77, 'end_character': 1427, 'bleu_score': 1.0, 'section': 'Section::::Course of the war.:British defeat in America (1781).\n'}]}, {'provenance': [{'wikipedia_id': '771', 'title': 'American Revolutionary War', 'start_paragraph_id': 77, 'start_character': 676, 'end_paragraph_id': 77, 'end_character': 1590, 'bleu_score': 0.9861583350689591, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10525276611139532849}, 'section': 'Section::::Course of the war.:British defeat in America (1781).\n'}]}]