Question: when was the mirage built in las vegas
[{'answer': '1989', 'provenance': [{'wikipedia_id': '1033455', 'title': 'The Mirage', 'start_paragraph_id': 11, 'start_character': 65, 'end_paragraph_id': 11, 'end_character': 69, 'bleu_score': 1.0, 'section': 'Section::::History.:Early years.\n'}]}]