Question: when did they change the wind chill formula
[{'answer': 'November 2001', 'provenance': [{'wikipedia_id': '154910', 'title': 'Wind chill', 'start_paragraph_id': 17, 'start_character': 3, 'end_paragraph_id': 17, 'end_character': 16, 'bleu_score': 1.0, 'section': 'Section::::Alternative approaches.:North American and United Kingdom wind chill index.\n'}]}, {'provenance': [{'wikipedia_id': '154910', 'title': 'Wind chill', 'start_paragraph_id': 17, 'start_character': 0, 'end_paragraph_id': 17, 'end_character': 708, 'bleu_score': 0.9155233861567761, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15807484287140326483}, 'section': 'Section::::Alternative approaches.:North American and United Kingdom wind chill index.\n'}]}]