Yes, these stats lump pretty much every denomination of a particular faith together; and there's nothing wrong with that, though I do believe there are more sunni muslims in the world than any other denomination (though that is also deceptive, since there are many groups in Sunni Islam that could be divided into different "denominations" too). Catholics are by far the largest denomination in Christianity.
Also, the 1.1 billion "atheists" is only if you count China's population as being "atheist", which they are officially, but that's pretty well by government decree, and in practice many people who are listed as "atheists" by Chinese nationality actually practice Buddhism, Taoism, Confucianism, or any combination of the three put together. There are also potentially as many as 100 million practitioners of Falun Gong, though that number is probably a gross overestimation. Even so, there's probably more Falun Gong practitioners in the world than there are Scientologists at the very least, and that 500k figure for Scientology is also a gross exaggeration.
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