Question: what percentage of the population has identical twins
[{'answer': '33.3 per 1,000 births'}, {'provenance': [{'wikipedia_id': '79238', 'title': 'Twin', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 96, 'bleu_score': 0.67331874553513, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15445662339494208447}, 'section': 'Section::::Statistics.\n'}]}]