Question: when did salt and pepper became a pair
[{'answer': 'seventeenth - century', 'provenance': [{'wikipedia_id': '16754210', 'title': 'Salt and pepper', 'start_paragraph_id': 2, 'start_character': 61, 'end_paragraph_id': 2, 'end_character': 87, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '16754210', 'title': 'Salt and pepper', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 542, 'bleu_score': 0.931147195580964, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9680309490453583370}, 'section': 'Section::::Abstract.'}]}]