Question: when did cavity wall insulation become part of building regulations
[{'answer': '1990s', 'provenance': [{'wikipedia_id': '5100937', 'title': 'Cavity wall', 'start_paragraph_id': 3, 'start_character': 482, 'end_paragraph_id': 3, 'end_character': 487, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '5100937', 'title': 'Cavity wall', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 487, 'bleu_score': 0.6231239125560181, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10976796058887718830}, 'section': 'Section::::History.\n'}]}]