Question: when was the last wolf pack killed in yellowstone
[{'answer': 'by 1926', 'provenance': [{'wikipedia_id': '24636908', 'title': 'History of wolves in Yellowstone', 'start_paragraph_id': 7, 'start_character': 109, 'end_paragraph_id': 7, 'end_character': 116, 'bleu_score': 1.0, 'section': 'Section::::Extirpation (1872–1926).\n'}]}, {'answer': '1926', 'provenance': [{'wikipedia_id': '24636908', 'title': 'History of wolves in Yellowstone', 'start_paragraph_id': 1, 'start_character': 419, 'end_paragraph_id': 1, 'end_character': 423, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '24636908', 'title': 'History of wolves in Yellowstone', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7912587081325165645}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '24636908', 'title': 'History of wolves in Yellowstone', 'start_paragraph_id': 7, 'start_character': 0, 'end_paragraph_id': 7, 'end_character': 563, 'bleu_score': 0.909913626309065, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7912587081325165645}, 'section': 'Section::::Extirpation (1872–1926).\n'}]}, {'provenance': [{'wikipedia_id': '24636908', 'title': 'History of wolves in Yellowstone', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 616, 'bleu_score': 0.978606533029418, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7912587081325165645}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '5444627', 'title': 'Wolf reintroduction', 'section': 'Section::::United States.:Yellowstone.\n', 'start_paragraph_id': 8, 'end_paragraph_id': 8, 'meta': {'evidence_span': ['1926 was the year that the last wolves were killed within Yellowstones boundaries.', 'Officially, 1926 was the year that the last wolves were killed within Yellowstones boundaries. When the wolves were eradicated and hunting eliminated, the elk population boomed', 'Officially, 1926 was the year that the last wolves were killed within Yellowstones boundaries.']}}]}, {'provenance': [{'wikipedia_id': '34340', 'title': 'Yellowstone National Park', 'section': 'Section::::Biology and ecology.:Fauna.\n', 'start_paragraph_id': 72, 'end_paragraph_id': 72, 'meta': {'evidence_span': ['Park Service hunters carried out these orders, and by 1926 they had killed 136 wolves, and wolves were virtually eliminated from Yellowstone.', 'Starting in 1914, in an effort to protect elk populations, the U.S. Congress appropriated funds to be used for the purposes of "destroying wolves, prairie dogs, and other animals injurious to agriculture and animal husbandry" on public lands. Park Service hunters carried out these orders, and by 1926 they had killed 136 wolves, and wolves were virtually eliminated from Yellowstone.']}}]}, {'provenance': [{'wikipedia_id': '24636908', 'title': 'History of wolves in Yellowstone', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['The last wolves were killed in Yellowstone in 1926.', 'The creation of the national park did not provide protection for wolves or other predators, and government predator control programs in the first decades of the 1900s essentially helped eliminate the gray wolf from Yellowstone. The last wolves were killed in Yellowstone in 1926.']}}]}]