Question: when was i know why the caged bird sings poem written
[{'answer': '1969', 'provenance': [{'wikipedia_id': '1219913', 'title': 'I Know Why the Caged Bird Sings', 'start_paragraph_id': 1, 'start_character': 37, 'end_paragraph_id': 1, 'end_character': 41, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1219913', 'title': 'I Know Why the Caged Bird Sings', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 650, 'bleu_score': 0.9612260133949071, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5164730262646811395}, 'section': 'Section::::Abstract.'}]}]