Question: when did the us not participate in the olympics
[{'answer': 'the 1980 Summer Olympics', 'provenance': [{'wikipedia_id': '2112059', 'title': 'United States at the Olympics', 'start_paragraph_id': 1, 'start_character': 118, 'end_paragraph_id': 1, 'end_character': 142, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '2112059', 'title': 'United States at the Olympics', 'start_paragraph_id': 1, 'start_character': 4, 'end_paragraph_id': 1, 'end_character': 273, 'bleu_score': 0.874678895739835, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8982093725469969747}, 'section': 'Section::::Abstract.'}]}]