Question: when did god save the king became national anthem
[{'answer': '1977', 'provenance': [{'wikipedia_id': '12334', 'title': 'God Save the Queen', 'start_paragraph_id': 2, 'start_character': 124, 'end_paragraph_id': 2, 'end_character': 128, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '12334', 'title': 'God Save the Queen', 'start_paragraph_id': 2, 'start_character': 47, 'end_paragraph_id': 2, 'end_character': 848, 'bleu_score': 0.8991475483354491, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6571372146620111410}, 'section': 'Section::::Abstract.'}]}]