Author: Spiros Kakos

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Religion-Science Philosophy articles series



The purpose of this article is not to say something in favour or against religion. The purpose of this article is to simply present hard data on the number of religion-affiliated people based on the most valid (and publicly available) sources, so that the readers can extract their own conclusions on spirituality in the world. I have made an attempt to use sources that can be found by everyone on the Internet, so that the validation of things written here is easy. Any comments and corrections are more than welcomed!

Difficulties in counting religious people

There is an inherent difficulty in counting the number of religion-affiliated people. The main difficulty has to do with the fact that there are no religion-related questions in census questionnaires. And if there are, in most cases they are not obligatory to answer. So one can understand that there is a difficult area to explore. Without official hard data, we must rely in most cases upon the surveys conducted by various individuals and private organizations, often with not the best intentions and certainly not with “truth” as their goal…The difficulty becomes more obvious if one thinks of the sensitiveness of the topic of religion. Most of the abovementioned organizations and individuals undertaking a statistical survey to record religiosity, are inclined in favour or against religion. That means that most surveys are biased towards one way or the other. Seeing the truth requires being alert for bias and ability to read between the lines. But we can do that…

Main sources

I have made an effort to find free and reliable sources for religion statistics. The task was not easy. I was surprised to see that Wikipedia had one of the most astounding collections of data for religiosity around the world – it seems that the collective effort of many people is unmatched these days. On the other hand, the official CIA Worldbook seems to be the most “official” data source one can find referring mainly to census data, even though I guess the data contained there are somewhat biased (although I admit I do not know in which direction). The main sources I have found during my investigation in the Internet are the following:

I. Wikipedia Main Articles


II. CIA Factbook


III. Adherents articles


IV. Britanicca articles


V. The future of religion

Study for the future of Religion: http://www.wnrf.org/cms/next200.shtml
Growth of religions: http://en.wikipedia.org/wiki/Fastest-growing_religion

Most of the above sources are free and constrantly updated and that is why they seem to be the best we have at this moment. The Global Christian Encyclopedia also is a good source of religion statistics, but it is not offered for free and that is why it is not included in the list. Any comments for new sources are welcomed.

Religion numbers

It would take hundrends of pages to just present all data from the abovementioned sources. That is why I will try to present the main data only for Christianity and Islam here. These are the two main religions in the world and their analysis offers a very good perspective of religiosity all over Earth.

Turkey, sex, oppression...

Christianity in the World

Here I will just show the numbers related to Christianity for some major developed countries of Europe. The source I use for these numbers is the respective page of Wikipedia for religion demographics. It seems that Christianity continues to hold a high and stable over the years percentage in western countries.

Country Population % Christian
Austria 8,199,783 78.3%
Belgium 10,392,226 48%
Bulgaria 7,322,858 84%(2001 census)
Cyprus 788,457 98.1%- 82%
Czech Republic 10,228,744 28.9%(2001 census)
Denmark 5,468,120 98% – 60%
Finland 5,238,460 84.7% (2006 census)
France 63,718,187 51% – 67%(2006 report)
Germany 82,400,996 68%
Greece 10,706,290 98%
Italy 58,147,733 90%
Luxembourg 480,222 87%
Malta 400,000 98%
the Netherlands 16,570,613 51% (2002)
Norway 4,627,926 90.1%
Poland 38,518,241 91.4% (2002)
Portugal 10,642,836 86.7% (2001 census)
Romania 22,276,056 99%(2002 census)
Russia 141,377,752 78%
Serbia 10,835,001 91.6% (2002 census)
Slovakia 5,447,502 83.8%
Slovenia 2,009,245 58.7%
Spain 40,448,191 76%
Sweden 9,031,088 87%
Switzerland 7,554,661 79.3%(2000 Census)
Ukraine 46,299,862 96.1% (2006 est.) 35%- 51.7%
the United Kingdom 60,776,238 71.6%(2001 Census)
the United States 301,139,947 78.5%(2007 est.)
Vatican City 921 100%

Source: Wikipedia [http://en.wikipedia.org/wiki/Christianity_by_country] [1]

[Retrieved at 24/12/2009]

From the above table one can easily understand that Christianity is still strong in all European countries, despite the hard materialism that some try to impose on the modern era. It seems that religiosity is not dying – quite the contrary. Countries where technology, fashion and consumer goods have a great footprint, still have a vast and stable majority of Christians in their populations.

Islam in the World

The statistics of countries is Middle East, Africa or Asia are more or less the same, but with Islam in the place of Christianism. The following table is again revaling of a very religious reality…

Country/Region % of total population
Afghanistan 99.7
Albania 79.9
Algeria 98.0
Azerbaijan 99.2
Bahrain 81.2
Bangladesh 89.6
Bosnia-Herzegovina 40
Brunei 67.2
Egypt 94.6
Eritrea 36.5
Ethiopia 33.9
Gambia 95
Indonesia 88.2
Iran 99.4
Iraq 99
Jordan 98.2
Kazakhstan 56.4
Kuwait 95
Libya 96.6
Malaysia 60.4
Morocco 99
Niger 98.6
Nigeria 50.4
Oman 87.7
Pakistan 96.3
Qatar 77.5
Saudi Arabia 97
Senegal 96.0
Sierra Leone 71.3
Somalia 98.5
Sudan 71.3
Syria 92.2
Tunisia 99.5
Turkey 98
Turkmenistan 93.1
United Arab Emirates 76.2
Uzbekistan 96.3
Yemen 99.1

Source: Wikipedia [http://en.wikipedia.org/wiki/Islam_by_country] [2]

[Retrieved at 24/12/2009]

From the abovementioned data it seems that people still believe that a First Cause must exist, as Aristotle once postulated… Religion is still alive despite the wishes of many…The atheism mystery…If one looks at the atheism numbers at http://en.wikipedia.org/wiki/Demographics_of_atheism he/she will be able to see one more interesting thing: the remaining percentages that are not Christians, are not atheists! Many people tend to claim they are “not religious” but on the same time they do not claim they are atheists. That leaves a lot of room for interpretations and theories. For me this is an indication that many people, although they tend to believe that there is something of “higher power” in the cosmos, they do not feel affiliated with any church because of the wrong-doings of those churches. Because if they were convinced that nothing like a God exists, then they would have no problem claiming “atheists”. As simple as that.

Religiosity statistics among scientists - A tale of oppression

Religion future trends

It is not an easy task to find the trends of religion. The reason is that many factors seem to affect the final result. The trends of religions depend upon the birth rates of already-religious people and it is not always possible to exclude that rate and calculate the “real” growth. From Wikipedia again we have the following numbers for the growth of the main religions:The World Christian Database (WCD) and its predecessor the World Christian Encyclopedia contains large amounts of data on numbers and growths of religions. The following is a tabulation of their results: (Note: The annual growth in the world population over the same period is 1.41%)

1970-1985 1990-2000 2000-2005
3.65% – Bahá’í Faith 2.65% – Zoroastrianism 1.84% – Islam
2.74% – Islam 2.28% – Bahá’í Faith 1.70% – Bahá’í Faith
2.34% – Hinduism 2.13% – Islam 1.62% – Sikhism
1.67% – Buddhism 1.87% – Sikhism 1.57% – Hinduism
1.64% – Christianity 1.69% – Hinduism 1.32% – Christianity
1.09% – Judaism 1.36% – Christianity
1.09% – Buddhism

Source: Wikipedia [http://en.wikipedia.org/wiki/Fastest-growing_religion] [3]

[Retrieved at 24/12/2009]

The Carnegie Endowment for International Peace using the 2000-2005 edition of the World Christian Database, concluded that high birth rates were the reason for the growth in all six; however, the growth of Christianity was also attributed to conversions. Although the World Christian Database does not cite sources, a review examining the reliability and bias of the WCD found it “highly correlated with other sources of data” but “consistently gave a higher estimate for percent Christian.” The Journal for the Scientific Study of Religion said that “on the whole we find that the WCD is reliable. Data from Encyclopedia Britanicca(which can be found at the same page) show more or less the same results, but with slightly more increased growth rates for Christianity, reaching to about 6% for the years 1995-2002.As for Islam, it seems to be getting stronger and stronger. The main reason for that seems to be the higher birth rates of Islam believers. Europe has already been witnessing such a growth withing its countries.


Many people argue that religion grows. Others argue that religion is declining. I say that number of religious people stay the same. From ancient times to now, the vast majority of people feel and logically understand the existence of a First Cause for the Universe. From ancient times to now, the vast majority of people feel and understand the intelligence the world has embedded in its mechanisms. And from ancient times to now, the vast majority of people feel and understand the existence of a higher purpose in life, other than just having sex, eating and going to the toilette. In Greece at the old days we worshiped the Moon. Then the 12-Gods religion came into place at the times of Plato and Aristotle. That was then replaced by Christianity. In the future another religion may take that place. No matter how it is called, people find it very hard to believe that they just happened to exist in the world where consuming chips and buying nice shoes is all there is…