Question: when was the last time port adelaide won a premiership
[{'answer': '1999', 'provenance': [{'wikipedia_id': '24602', 'title': 'Port Adelaide Football Club', 'start_paragraph_id': 46, 'start_character': 11, 'end_paragraph_id': 46, 'end_character': 15, 'bleu_score': 1.0, 'section': 'Section::::Club history.:1974–1998: John Cahill, SANFL domination and AFL entry.\n'}]}]