Question: when did the us stop using lead pipes
[{'answer': '1986', 'provenance': [{'wikipedia_id': '43982', 'title': 'Plumbing', 'start_paragraph_id': 48, 'start_character': 540, 'end_paragraph_id': 48, 'end_character': 544, 'bleu_score': 1.0, 'section': 'Section::::Difference between pipes and tubes.:Materials.:Plastic.\n'}]}, {'provenance': [{'wikipedia_id': '43982', 'title': 'Plumbing', 'start_paragraph_id': 48, 'start_character': 0, 'end_paragraph_id': 48, 'end_character': 613, 'bleu_score': 0.957165036755604, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15514249556464683092}, 'section': 'Section::::Difference between pipes and tubes.:Materials.:Plastic.\n'}]}]