Question: when was the last time la hosted the olympics
[{'answer': '1984', 'provenance': [{'wikipedia_id': '1337290', 'title': 'Los Angeles Olympics', 'start_paragraph_id': 1, 'start_character': 49, 'end_paragraph_id': 1, 'end_character': 53, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]