Question: when did panama canal go back to panama
[{'answer': '1999', 'provenance': [{'wikipedia_id': '24849', 'title': 'Panama Canal', 'start_paragraph_id': 3, 'start_character': 315, 'end_paragraph_id': 3, 'end_character': 319, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '24849', 'title': 'Panama Canal', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 453, 'bleu_score': 0.9357502588195491, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 529358499353160371}, 'section': 'Section::::Abstract.'}]}]