Question: when was the last time the us had a budget surplus
[{'answer': '2001', 'provenance': [{'wikipedia_id': '5878495', 'title': 'History of the United States public debt', 'start_paragraph_id': 27, 'start_character': 626, 'end_paragraph_id': 27, 'end_character': 630, 'bleu_score': 1.0, 'section': 'Section::::After World War II.\n'}]}, {'provenance': [{'wikipedia_id': '5878495', 'title': 'History of the United States public debt', 'start_paragraph_id': 37, 'start_character': 0, 'end_paragraph_id': 37, 'end_character': 658, 'bleu_score': 0.980097014099621, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17303457562477678461}, 'section': 'Section::::Causes of recent changes in debt.:2001 vs. 2009.\n'}]}]