Question: what is the percentage of single parents in america
[{'answer': '28 %', 'provenance': [{'wikipedia_id': '226109', 'title': 'Single parent', 'start_paragraph_id': 69, 'start_character': 261, 'end_paragraph_id': 69, 'end_character': 267, 'bleu_score': 1.0, 'section': 'Section::::United States.\n'}]}]