Question: Poker Joe, was a warrior and subchief of the Nez Percé tribe of Native Americans who played a critical role during the flight of the Nez Percé during the Nez Percé War in which year, he was the chosen trail boss and guide of the Nez Percé people following the Battle of the Big Hole?
{'answer': '1877', 'supporting_facts': [['Poker Joe', 0], ['Battle of the Big Hole', 0]]}