Estimates for atheism alone (as a primary religious preference) range from 200 to 240 million. But these come primarily from China and former Soviet Union nations (especially Russia). Prior to Communist takeovers of these regions and government attempts to eradicate religion, both places had very high levels of affiliation with organized religions (especially Islam, Christianity, Buddhism and Taoism), as well as high levels of participation in and belief in traditional local traditions such as shamanism, ancestor ceremonies, spiritism, etc. Since the fall of Communism in former Soviet nations and the relaxation of anti-religious policies in China, observed religious affiliation and activity has increased dramatically, especially in Christianity, Buddhism, and Islam.
China probably does have the largest number of actual atheists of any country in the world and many Russians clearly remain atheists. But at this point, it is difficult to accurately determine how many of those classified as atheists or nonreligious during Communist-era USSR and by the current Chinese government are actually atheists according to their personal beliefs, and how many are unregistered religious adherents or participants in less-organized traditional systems that are oriented around ancestors, animism, shamanism, etc. Many people are unaware, for instance, that China has one of the largest, most active Christian communities in the world, and that in many former Soviet nations religions such as shamanism, Islam and Russian Orthodoxy remained even while official government reports announced the elimination of religion in these regions.
