Question: when did the nuclear stockpile of the united states peak
[{'answer': '1967', 'provenance': [{'wikipedia_id': '2032576', 'title': 'Nuclear weapons of the United States', 'start_paragraph_id': 84, 'start_character': 297, 'end_paragraph_id': 84, 'end_character': 301, 'bleu_score': 1.0, 'section': 'Section::::Current status.\n'}]}, {'provenance': [{'wikipedia_id': '2032576', 'title': 'Nuclear weapons of the United States', 'start_paragraph_id': 84, 'start_character': 0, 'end_paragraph_id': 84, 'end_character': 585, 'bleu_score': 0.9536330554540541, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11293937021259458417}, 'section': 'Section::::Current status.\n'}]}]