Question: when was the secret ballot introduced in the us
[{'answer': 'around 1890', 'provenance': [{'wikipedia_id': '479210', 'title': 'Secret ballot', 'start_paragraph_id': 24, 'start_character': 212, 'end_paragraph_id': 24, 'end_character': 223, 'bleu_score': 1.0, 'section': 'Section::::History.:United States.\n'}]}, {'provenance': [{'wikipedia_id': '479210', 'title': 'Secret ballot', 'start_paragraph_id': 24, 'start_character': 0, 'end_paragraph_id': 24, 'end_character': 347, 'bleu_score': 0.96188712955549, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5305031279216718833}, 'section': 'Section::::History.:United States.\n'}]}]