Question: what percent of schools wear uniforms in the us
[{'answer': '20', 'provenance': [{'wikipedia_id': '41018063', 'title': 'School uniforms by country', 'start_paragraph_id': 22, 'start_character': 966, 'end_paragraph_id': 22, 'end_character': 968, 'bleu_score': 1.0, 'section': 'Section::::Canada.\n'}]}, {'provenance': [{'wikipedia_id': '41018063', 'title': 'School uniforms by country', 'start_paragraph_id': 243, 'start_character': 0, 'end_paragraph_id': 243, 'end_character': 557, 'bleu_score': 0.977397480575333, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5031416422641098941}, 'section': 'Section::::United States.\n'}]}]