Question: when did the united states last host the winter olympics
[{'answer': '2002', 'provenance': [{'wikipedia_id': '34069', 'title': 'Winter Olympic Games', 'start_paragraph_id': 4, 'start_character': 167, 'end_paragraph_id': 4, 'end_character': 171, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]