Question: when was the bunker built at the greenbrier
[{'answer': 'from 1959 to 1962', 'provenance': [{'wikipedia_id': '418979', 'title': 'The Greenbrier', 'start_paragraph_id': 20, 'start_character': 349, 'end_paragraph_id': 20, 'end_character': 366, 'bleu_score': 1.0, 'section': 'Section::::History.:The Bunker.\n'}]}, {'provenance': [{'wikipedia_id': '418979', 'title': 'The Greenbrier', 'start_paragraph_id': 20, 'start_character': 0, 'end_paragraph_id': 20, 'end_character': 366, 'bleu_score': 0.9663744727315161, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7767664047306208089}, 'section': 'Section::::History.:The Bunker.\n'}]}]