Question: when did the oldest human occupation of meadowcroft rockshelter occur
[{'answer': '16,000 years ago', 'provenance': [{'wikipedia_id': '4212686', 'title': 'Meadowcroft Rockshelter', 'start_paragraph_id': 12, 'start_character': 61, 'end_paragraph_id': 12, 'end_character': 77, 'bleu_score': 1.0, 'section': 'Section::::Archaeology.:Dating.\n'}]}, {'provenance': [{'wikipedia_id': '4212686', 'title': 'Meadowcroft Rockshelter', 'start_paragraph_id': 12, 'start_character': 0, 'end_paragraph_id': 12, 'end_character': 1100, 'bleu_score': 0.9635550667469601, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8855427816970987040}, 'section': 'Section::::Archaeology.:Dating.\n'}]}]