Question: in index number of which year price is assumed to be 100
[{'answer': '2000', 'provenance': [{'wikipedia_id': '1355939', 'title': 'Price index', 'start_paragraph_id': 41, 'start_character': 389, 'end_paragraph_id': 41, 'end_character': 393, 'bleu_score': 1.0, 'section': 'Section::::Formal calculation.:Practical measurement considerations.:Normalizing index numbers.\n'}]}]