Question: when was the last time the raiders won a championship
[{'answer': '2002', 'provenance': [{'wikipedia_id': '22312', 'title': 'Oakland Raiders', 'start_paragraph_id': 2, 'start_character': 744, 'end_paragraph_id': 2, 'end_character': 748, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]