Question: when was the south african national anthem officially adopted
[{'answer': 'in 1997', 'provenance': [{'wikipedia_id': '30944', 'title': 'National anthem of South Africa', 'start_paragraph_id': 1, 'start_character': 48, 'end_paragraph_id': 1, 'end_character': 55, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '30944', 'title': 'National anthem of South Africa', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 331, 'bleu_score': 0.669891228216909, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12559882904446340264}, 'section': 'Section::::Abstract.'}]}]