Question: when did the first chevy silverado come out
[{'answer': '1998', 'provenance': [{'wikipedia_id': '865341', 'title': 'Chevrolet Silverado', 'start_paragraph_id': 1, 'start_character': 183, 'end_paragraph_id': 1, 'end_character': 187, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '865341', 'title': 'Chevrolet Silverado', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 563, 'bleu_score': 0.979484453366057, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7939512308892587}, 'section': 'Section::::Abstract.'}]}]