Question: when did us give up control of panama canal
[{'answer': '1979', 'provenance': [{'wikipedia_id': '315787', 'title': 'Panama Canal Zone', 'start_paragraph_id': 1, 'start_character': 91, 'end_paragraph_id': 1, 'end_character': 95, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '315787', 'title': 'Panama Canal Zone', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 679, 'bleu_score': 0.7972668934795131, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5042380179436835405}, 'section': 'Section::::Abstract.'}]}]