This is a highly disparate group. Most current estimates of the numbers of people identifying themselves as secular, non-religious, agnostic or atheist are between 800 and 1 billion people, but the figure could be as high as 20% of the world population, or about 1.2 billion: “Over 20 percent of the world’s population does not claim any allegiance to a religion. Most are agnostics… others are atheists who deny the existence of God.”[1] But such a high figure is difficult to support and perhaps reflects Communist-era official government statistics. Prior to Communist takeovers and government attempts to eradicate religion, countries such as China and Russia had very high levels of affiliation with organized religions, particularly Islam, Christianity, Buddhism and Taoism, as well as high levels of participation in and belief in traditional local traditions such as shamanism, ancestor worship and spiritism. Since the fall of Communism in former Soviet nations and the relaxation of anti-religious policies in China, religious affiliation and activity, particularly in Christianity, Buddhism and Islam has increased dramatically.
People who specify atheism as their religious preference actually make up less than one-half of one percent of the population in many countries where much larger numbers claim no religious preference, such as theUnited StatesandAustralia.
One portion of this broad grouping includes those who describe themselves as “non-religious,” in other words, those who don’t belong to an organized religion. This group may or may not contemplate philosophical and spiritual matters and may or may not be involved in a religious, faith or philosophical community. “Non-religious” is not equated with non-belief in God or a Higher Power, as many people in this category expressly do have this belief.
The use of the term “non-religious” or “secular” can refer to belief, or participation in systems which are not traditionally labeled “religions”. However, in the absence of traditional religions, society may exhibit the same behavioral, social and psychological phenomena associated with religious cultures but in association with secular, political, ethnic, commercial or other activities. Marxism and Maoism, for instance, had their scriptures, authority, symbolism, liturgy, clergy, prophets, proselytizing and etc. Sports, art, patriotism, music, drugs, mass media and social causes have all been observed to fulfill roles similar to religion in the lives of individuals, capturing the imagination and serving as a source of values, beliefs and social interaction.
In a broader sense, sociologists point out that there are no truly “secular societies,” and that the word “non-religious” is a misnomer. Sociologically speaking, “non-religious” people are simply those who derive their worldview and value system primarily from alternative, secular, cultural or otherwise non-revealed systems rather than traditional religious systems. Like traditional religions, secular systems (such as Communism, Platonism, Freudian and Jungian psychology, Nazism, pantheism, atheism or nationalism) typically have favored spokespeople and claim to present a universally valid and applicable “truth”.
This group also includes more proactive or well-defined philosophies such as secular humanism, atheism, agnosticism, deism, pantheism and freethought, most of which can be classified as religions in the sociological sense, albeit secular religions.
In the Western world, Europe has the most self-avowed non-religious, atheists and agnostics (41 million) with the numbers particularly high in Scandinavia. The self-described non-religious segment of society in Australia and New Zealand is also high, at around 15%.
[1] (O’Brien, Joanne and Palmer, Martin, The State of Religion Atlas, Simon & Schuster: New York, 1993, p 41.)
interfaith 
Being a former Minister and Freethinker who is not anti-religious I would respond to several statements here (and I have commented elsewhere about a community congregation concept). It is unfortunate that this article tends to perpetuate some myths about non-theism. We are not simply “anti” everything (non, anti, a-theist, etc.). In fact, some of us are quite active in good and positive ways in our common, and yes, secular world (“secular”: this present world). Those of us who no longer believe in a supernatural are not members of some new secular religion. We do not have “scriptures” and “clergy” and “prophets.” We do not have “faith.” This does not mean that we do not find teachers of wisdom in many circles including religious. Yet, we have not simply chosen another worldview to proclaim a new “truth.” Those who choose a super-natural worldview rather than a natural have chosen and offer an “alternative” to the world we live in. Some of us may feel that distracts from the common tasks and may hinder creative human community. Yet, please do not merely list Freethinkers with Nazis, Communists and Freudians. The “universally valid truth” some of us teach and write about is seeking the good, the right, the just, for everyone, to follow our natural reason and to work for Good, whether or not there is a God. Lastly, thank you for including this page on an interfaith site. We have much to learn from each other!
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