context: Liu Ju (Chinese: 劉 據; 128- 91 BC), officially known as Crown Prince Wei (衛 太子) and posthumously as Crown Prince Li (戾 太子, literally "the Crown Prince does not repent ") was a crown prince from the Western Han Dynasty. He was the eldest son and heir to his father, Emperor Wu of Han, until his death at the age of 38 during a political turmoil in 91 BC. Contrary to the less flattering posthumous name, Liu Ju is generally regarded by historians as a polite, kind, and moral person who, due to circumstances beyond his control, was forced into rebellion against his father's army and died as a consequence of the rebellion.
question: When did Liu Ju die?
answers.text: 91 BC