Question: when did grand teton become a national park
[{'answer': 'February 26 , 1929', 'provenance': [{'wikipedia_id': '35604167', 'title': 'Establishment of Grand Teton National Park', 'start_paragraph_id': 1, 'start_character': 1930, 'end_paragraph_id': 1, 'end_character': 1948, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '35604167', 'title': 'Establishment of Grand Teton National Park', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 1947, 'bleu_score': 0.943418119401163, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17300809165059437958}, 'section': 'Section::::Abstract.'}]}]