Question: when was kevlar first used as body armor
[{'answer': 'In the mid-1970s', 'provenance': [{'wikipedia_id': '149058', 'title': 'Bulletproof vest', 'start_paragraph_id': 38, 'start_character': 279, 'end_paragraph_id': 38, 'end_character': 295, 'bleu_score': 1.0, 'section': 'Section::::History.:Postwar.\n'}]}, {'provenance': [{'wikipedia_id': '149058', 'title': 'Bulletproof vest', 'start_paragraph_id': 38, 'start_character': 0, 'end_paragraph_id': 38, 'end_character': 845, 'bleu_score': 0.965400604802336, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15347369509371104709}, 'section': 'Section::::History.:Postwar.\n'}]}]