Question: when was the reaper invented by cyrus mccormick
[{'answer': '1834', 'provenance': [{'wikipedia_id': '360310', 'title': 'Reaper', 'start_paragraph_id': 17, 'start_character': 328, 'end_paragraph_id': 17, 'end_character': 332, 'bleu_score': 1.0, 'section': 'Section::::Mechanical reaping.:Mechanical reapers in the U.S..\n'}]}, {'answer': '1837'}, {'provenance': [{'wikipedia_id': '360310', 'title': 'Reaper', 'start_paragraph_id': 17, 'start_character': 0, 'end_paragraph_id': 17, 'end_character': 449, 'bleu_score': 0.9383908431221111, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10080577661012566291}, 'section': 'Section::::Mechanical reaping.:Mechanical reapers in the U.S..\n'}]}, {'provenance': [{'wikipedia_id': '360310', 'title': 'Reaper', 'start_paragraph_id': 23, 'start_character': 0, 'end_paragraph_id': 23, 'end_character': 271, 'bleu_score': 0.9000283069718911, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10080577661012566291}, 'section': 'Section::::Mechanical reaping.:Mechanical reapers in the U.S..\n'}]}, {'provenance': [{'wikipedia_id': '29432015', 'title': 'Productivity improving technologies', 'section': 'Section::::Major sources of productivity growth in economic history.:Mechanization.:Mechanized agriculture.\n', 'start_paragraph_id': 66, 'end_paragraph_id': 66, 'meta': {'evidence_span': ["the 1860s threshing machines were widely introduced and ultimately displaced as much as a quarter of agricultural labor. In Europe, many of the displaced workers were driven to the brink of starvation. Before c. 1790 a worker could harvest 1/4 acre per day with a scythe. In the early 1800s the grain cradle was introduced, significantly increasing the productivity of hand labor. It was estimated that each of Cyrus McCormick's horse pulled reapers (Ptd. 1834) freed up five men for military service in the U.S. Civil War. By 1890 two men and two horses could cut, rake and bind 20 acres of wheat per day.\rhighlight sentence(s) containing evidence, not only the answer", "It was estimated that each of Cyrus McCormick's horse pulled reapers (Ptd. 1834)"]}}]}]