百不获一

Explanation: By: be. Not get into a hundred. Describe the person or thing is extremely rare 　　Usage: Contraction type; as object, attribute; that is extremely rare 　　Source: Ching Lee Greenwood "Qiludeng" 150 back: "Since the character will be correct, the text will be clear shift from the smooth, intelligible, natural indeed, not be one hundred."