This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Knowing how many people in a country belong to a given tradition sounds like a simple counting problem and rarely is. Many national censuses do not ask about religion at all, some ask but let a respondent decline to answer, and self-identification on a form frequently disagrees with how regularly a person actually practices, so any single figure is really an answer to one specific question asked one specific way. Earlier estimates, drawn largely from missionary records through the first half of the twentieth century, have gradually been replaced by survey based social science with clearer, published methodology.
Two projects now anchor most current global figures: the World Religion Database, which compiles country level adherence data across every major and most minor traditions worldwide, and comparable large scale survey work from research organizations that publish their sampling methods openly. Neither claims certainty down to the last percentage point, and a careful country entry says so, treating a demographic figure as the best available estimate under a stated method rather than as a fixed fact.
Comparing figures across two different studies of the same country is itself a common source of apparent contradiction that is really just a difference in method, a census question worded one way against a survey worded another, and the atlas notes which source a figure comes from precisely so that kind of mismatch can be understood rather than mistaken for a real disagreement about the facts.