Question: how many prime ministers in the queen's reign
[{'answer': '160'}, {'provenance': [{'wikipedia_id': '718792', 'title': 'List of prime ministers of Elizabeth II', 'start_paragraph_id': 3, 'start_character': 22, 'end_paragraph_id': 3, 'end_character': 481, 'bleu_score': 0.6795427350859721, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8271984909373114779}, 'section': 'Section::::Abstract.'}]}]