Question: when was the last census done in india
[{'answer': '31 March 2011', 'provenance': [{'wikipedia_id': '26787409', 'title': '2011 Census of India', 'start_paragraph_id': 1, 'start_character': 688, 'end_paragraph_id': 1, 'end_character': 701, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '26787409', 'title': '2011 Census of India', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 907, 'bleu_score': 0.877584396513129, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6105319343038102416}, 'section': 'Section::::Abstract.'}]}]