Question: when was the last time the bucks won a playoff series
[{'answer': '1971', 'provenance': [{'wikipedia_id': '15679645', 'title': 'List of Milwaukee Bucks seasons', 'start_paragraph_id': 1, 'start_character': 178, 'end_paragraph_id': 1, 'end_character': 182, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]