difficulty to obtain empirical data on the number of Christians in China, a series of surveys have been conducted and published by different agencies. Government figures only count adult baptized members of government sanctioned churches. Thus they generally do not include un-baptized persons attending Christian groups, non-adult children of Christian believers or other persons under age 18 and they generally do not take into account unregistered Christian groups. There is often significant overlap between the membership of registered and unregistered Christian bodies, as a large number of people attend both registered and unregistered churches. Official membership The Three-Self Church had a membership of 20 million people as of 2012. The Catholic Patriotic Church had a membership of 6 million people as of 2012. Independent surveys : three surveys of religions in China conducted in those years by the Horizon Research Consultancy Group on a disproportionately urban and suburban sampling, found that Christians constituted between 2% and 4% of the total population. 2007: two surveys were conducted that year to count the number of Christians in China. One of them was conducted by the Protestant missionary Werner Bürklin, founder of "China Partner", an international Christian organisation, and his team of 7,409 surveyors in every province and municipality of China. The other survey was conducted by professor Liu Zhongyu of the East China Normal University of Shanghai. The surveys were conducted independently and along different periods of time, but they reached the same results.Mark Ellis: New China survey reveals fewer Christians than most estimates Christian Examiner, November 2007. According to the analyses, there were approximately 54 million Christians in China (~4% of the total population), of whom 39 million were Protestants and 14 million were Catholics. 2008: a survey of religions conducted in that year by Yu Tao of the University of Oxford with a survey scheme led and supervised by the Center for Chinese Agricultural Policy (CCAP) and the Peking University, analysing the rural populations of the six provinces of Jiangsu, Sichuan, Shaanxi, Jilin, Hebei and Fujian, each representing different geographic and economic regions of China, found that Christians constituted approximately 4% of the population, of whom 3.54% were Protestants and 0.49% were Catholics. 2008–2009: a household survey conducted by the Chinese Academy of Social Sciences (CASS) counted 23 million Protestants (independent and registered) in China. 2010: the "Chinese Spiritual Life Survey" counted 33 million Christians (~2% of the total population),