Question: when did gateway arch become a national park
[{'answer': 'February 22 , 2018', 'provenance': [{'wikipedia_id': '49457', 'title': 'Gateway Arch National Park', 'start_paragraph_id': 63, 'start_character': 237, 'end_paragraph_id': 63, 'end_character': 255, 'bleu_score': 1.0, 'section': 'Section::::History.:2010s.\n'}]}, {'provenance': [{'wikipedia_id': '49457', 'title': 'Gateway Arch National Park', 'start_paragraph_id': 63, 'start_character': 0, 'end_paragraph_id': 63, 'end_character': 254, 'bleu_score': 0.8034512038068881, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2828757819131836351}, 'section': 'Section::::History.:2010s.\n'}]}]