Question: when did wendys come out with vanilla frosty
[{'answer': '2006', 'provenance': [{'wikipedia_id': '1251896', 'title': 'Frosty (frozen dairy dessert)', 'start_paragraph_id': 1, 'start_character': 403, 'end_paragraph_id': 1, 'end_character': 407, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]