Question: when did louisiana became a part of the united states
[{'answer': 'April 30 , 1812', 'provenance': [{'wikipedia_id': '18130', 'title': 'Louisiana', 'start_paragraph_id': 122, 'start_character': 46, 'end_paragraph_id': 122, 'end_character': 61, 'bleu_score': 1.0, 'section': 'Section::::History.:Statehood (1812).\n'}]}]