Question: when is the last time the us won the world cup
[{'answer': '1950', 'provenance': [{'wikipedia_id': '582488', 'title': "United States men's national soccer team", 'start_paragraph_id': 2, 'start_character': 149, 'end_paragraph_id': 2, 'end_character': 153, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '582488', 'title': "United States men's national soccer team", 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 941, 'bleu_score': 0.5814084497865021, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10935680611335266110}, 'section': 'Section::::Abstract.'}]}]