Question: when did they lower the pitcher's mound
[{'answer': '1969', 'provenance': [{'wikipedia_id': '968099', 'title': 'Baseball field', 'start_paragraph_id': 32, 'start_character': 384, 'end_paragraph_id': 32, 'end_character': 388, 'bleu_score': 1.0, 'section': "Section::::Pitcher's mound.\n"}]}, {'provenance': [{'wikipedia_id': '968099', 'title': 'Baseball field', 'start_paragraph_id': 32, 'start_character': 0, 'end_paragraph_id': 32, 'end_character': 688, 'bleu_score': 0.9828310228624961, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6601097166295925354}, 'section': "Section::::Pitcher's mound.\n"}]}]