Question: when did nike start the just do it campaign
[{'answer': '1988', 'provenance': [{'wikipedia_id': '36405660', 'title': 'Just Do It', 'start_paragraph_id': 1, 'start_character': 180, 'end_paragraph_id': 1, 'end_character': 184, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '36405660', 'title': 'Just Do It', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 651, 'bleu_score': 0.6078813703040951, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11523983982064465862}, 'section': 'Section::::Campaign.\n'}]}]