Question: when was the best animated feature film category first introduced
[{'answer': '2001', 'provenance': [{'wikipedia_id': '61830', 'title': 'Academy Award for Best Animated Feature', 'start_paragraph_id': 1, 'start_character': 480, 'end_paragraph_id': 1, 'end_character': 484, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]