The Chinese civil service examination system, as I understand it, allowed any learned male who could pass the exams a chance at a government position. However, the reality is that probably a large percentage of those taking the exams were still of the upper class due to the fact they had the financial resources and time to pass the exams. Has any scholar done estimates as to the percentages of those government officials who came from the upper class, middle class, and lower class? Is there any story of a lower class peasant rising up to the ranks of government by successfully passing the civil service exam?