Question: when did lusaka become the capital of zambia
[{'answer': '1964', 'provenance': [{'wikipedia_id': '23149963', 'title': 'Lusaka', 'start_paragraph_id': 5, 'start_character': 199, 'end_paragraph_id': 5, 'end_character': 203, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '23149963', 'title': 'Lusaka', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 262, 'bleu_score': 0.9560167778278961, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15341733433769079903}, 'section': 'Section::::History.\n'}]}]