Question: when did the us cut off trade with cuba
[{'answer': '1961', 'provenance': [{'wikipedia_id': '5231073', 'title': 'Cuba–United States relations', 'start_paragraph_id': 1, 'start_character': 226, 'end_paragraph_id': 1, 'end_character': 230, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': '1962', 'provenance': [{'wikipedia_id': '5231073', 'title': 'Cuba–United States relations', 'start_paragraph_id': 3, 'start_character': 458, 'end_paragraph_id': 3, 'end_character': 462, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '5231073', 'title': 'Cuba–United States relations', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 502, 'bleu_score': 0.535604281282403, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18101155455606676625}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '5231073', 'title': 'Cuba–United States relations', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18101155455606676625}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '5231073', 'title': 'Cuba–United States relations', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 562, 'bleu_score': 0.667753231725508, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18101155455606676625}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '5231073', 'title': 'Cuba–United States relations', 'start_paragraph_id': 32, 'start_character': 0, 'end_paragraph_id': 32, 'end_character': 420, 'bleu_score': 0.9318557434050331, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18101155455606676625}, 'section': 'Section::::Historical background.:Post-revolution relations.\n'}]}, {'provenance': [{'wikipedia_id': '5231073', 'title': 'CubaUnited States relations', 'section': 'Section::::Abstract.', 'start_paragraph_id': 3, 'end_paragraph_id': 3, 'meta': {'evidence_span': ['In 1961, the U.S. severed diplomatic ties with Cuba and began pursuing covert operations to topple the Cuban government.', "The 1961 Bay of Pigs Invasion, the 1962 missile crisis, and American efforts to stand up to Fidel Castro's attempts to spread communism throughout Latin America and", "The 1961 Bay of Pigs Invasion, the 1962 missile crisis, and American efforts to stand up to Fidel Castro's attempts to spread communism throughout Latin America and Africa, are main highlights of U.S. antagonism towards Cuba during the Cold War, although Nixon, Ford, Kennedy, and Johnson resorted to back-channel talks with the Cuban government during the Cold War."]}}]}]