Question: when did islamabad became the capital of pakistan
[{'answer': '1966', 'provenance': [{'wikipedia_id': '51153', 'title': 'Islamabad', 'start_paragraph_id': 16, 'start_character': 742, 'end_paragraph_id': 16, 'end_character': 746, 'bleu_score': 1.0, 'section': 'Section::::History.:Construction and development.\n'}]}, {'provenance': [{'wikipedia_id': '51153', 'title': 'Islamabad', 'start_paragraph_id': 16, 'start_character': 0, 'end_paragraph_id': 16, 'end_character': 746, 'bleu_score': 0.9262857197456471, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4150385740779291608}, 'section': 'Section::::History.:Construction and development.\n'}]}]