Question: when did dragon ball z manga come out
[{'answer': '1988', 'provenance': [{'wikipedia_id': '40006090', 'title': 'Dragon Ball Z', 'start_paragraph_id': 10, 'start_character': 125, 'end_paragraph_id': 10, 'end_character': 129, 'bleu_score': 1.0, 'section': 'Section::::Production and broadcasting.\n'}]}, {'provenance': [{'wikipedia_id': '40006090', 'title': 'Dragon Ball Z', 'start_paragraph_id': 10, 'start_character': 0, 'end_paragraph_id': 10, 'end_character': 696, 'bleu_score': 0.9831208473513011, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16789809628817993817}, 'section': 'Section::::Production and broadcasting.\n'}]}]