Question: when did psa airlines go out of business
[{'answer': '1988', 'provenance': [{'wikipedia_id': '346946', 'title': 'Pacific Southwest Airlines', 'start_paragraph_id': 1, 'start_character': 128, 'end_paragraph_id': 1, 'end_character': 132, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '346946', 'title': 'Pacific Southwest Airlines', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 456, 'bleu_score': 0.972782728923768, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8900011466497367530}, 'section': 'Section::::Abstract.'}]}]