Question: when did the united states surplus in international trade end
[{'answer': 'in 1975', 'provenance': [{'wikipedia_id': '23794617', 'title': 'Foreign trade of the United States', 'start_paragraph_id': 21, 'start_character': 32, 'end_paragraph_id': 21, 'end_character': 39, 'bleu_score': 1.0, 'section': 'Section::::Trade policy.\n'}]}, {'provenance': [{'wikipedia_id': '23794617', 'title': 'Foreign trade of the United States', 'start_paragraph_id': 22, 'start_character': 0, 'end_paragraph_id': 22, 'end_character': 452, 'bleu_score': 0.7788625852468001, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17747727004332072843}, 'section': 'Section::::Trade policy.\n'}]}]