The percentage of Christians in the world population has been steadily declining. I live in Western Europe, where, in fact, the percentage of decline is the highest in the world. This situation has been the subject of many articles and reports. Often the institutional church is on the receiving end of the blame, but God Himself is often fingered as well. Some believe that many church leavers remain committed but, fed up with institutional church hypocrisy, have found their own avenues to spiritual fulfillment.
Apart from my own corner of the Christian world are many areas in which the percentages of Christian population are indeed growing. Therefore, it is thought to be worthwhile to examine the available data systematically on a world-wide basis in order to discover the details: Where is Christianity growing, where declining? Are there lessons hidden in the numbers? Furthermore, in today’s world, we consider it of importance to answer the same questions in relation to the second dominant religion, namely Islam.
Global Distributions of Christians and Muslims around the world: 1900 to 2010
Based on raw data on the total populations of Christians and Muslims as provided by Operation World (OW) (1), Global Mapping International (GMI) (2) has produced a series of charts for various years in the past century. A selection of the GMI charts appears in Figure 1 for the years 1910 till 2010. The tabular data from which these charts were produced are listed in Table 1.
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Figure 1. Population distributions of Christians and Muslims around the world over the period from 1900 to 2020 (OW)
Table 1. Population distributions around the world for Christians and Muslims for various years between 1900 and 2010 (OW). Numbers *1000.
It is important to keep in mind that these data represent absolute numbers of people. To obtain a measure of the relative growth or decline of each religion over time, it is necessary to examine the respective percentages of Christians and Muslims on an area-by-area basis with respect to their respective total populations. This is necessary to factor out changes in the world population itself. Nevertheless, the maps in Figure 1 do clearly portray the geographical spread with time of the two dominant religions. Note the striking increases of Christianity in certain regions, especially Africa (particularly in the Sub-Sahara region), a few countries in South America (e.g., Brazil and the northwestern area of South America), and in some countries in Asia (especially China and the Philippines).
Percentage Populations of Christians and Muslims For Continents and Regions
One of the most extensive and reliable sources for information on religious groups is the World Christian Database (WCR) (3), which contains population data broken down into geographic and other subdivisions by year. Using these data we have calculated the required percentages for the world as a whole as given in Table 2. From an examination of the figures in Table 2 we can see that, over the period covered, the total global percentage of Christians has declined slightly while that of Islam has strongly increased—in fact, by almost a factor of two.
Table 2. Percentages of global population of Christians and Muslims for various years between 1900 and 2010 based on WCD figures
It is often much easier to digest the significance of data that are presented in graphical form than to do so from tables of raw numbers. For example, in Figure 2 we see displayed the information from Table 2 for both Christian and Muslims. In this way we can readily see the worldwide development of each group with time in considerable detail. Because the total percentage of Christians depends on changes in those of its various subset denominations, we include the separate data from Roman Catholics and Protestants as well.
Figure 2. Historical statistical relative development of Christian and Muslims global populations for the entire world population over the period from 1900 to 2010. Included are Christian subset denominations of Roman Catholic and Protestant (WCD)
The behaviors revealed in Figure 2 suggest that it might be very interesting to examine whether there are significant developments over the years on a continental or regional basis that might cast light on the origins of the changes that are revealed in the figure. In the process of sub-dividing continents into regions, we have used the official United Nations (UN) designators (4). Several recently published studies by the PEW Research Foundation have been particularly useful in our present effort (5,6,7). The Pew Forum found that 157 countries have majority Christian populations, while 49 have majority Muslim populations.
Focus on Continents
In Table 3, Overall percentage changes in Christian and Muslim populations are broken down summarized and presented for the six continents of the world for the period of 1900 through 2010. Significantly, according to these data, there is no continent on which the percentage of Muslims has decreased.
Table 3. Changes of percentages of Christian and Muslim populations broken down by continent for the period of 1900 to 2010 (WCD)
More details per continent can be find in the different Menu’s.
Systematic examination of the available data on the development of Christianity and Islam in the world from 1900 till 2010 reveals several key points:
- A slight decline of less than 2% was seen in the total global percentage of Christians
- The largest percentage decrease (-30%) in Christian population in the entire world occurred in Western Europe
- Strong growths in both Africa and Asia in the percentages of Christians were seen
- A nearly doubled percentage of Muslims took place on a global basis
- Advances in the percentages of Muslims occurred on every continent except Latin America, where, within measurement error, the percentage remained constant but low
1) Operation World, www.operationworld.org. Data available by subscription at ivpress
2) Global Mapping International, www.gmi.com Maps available by special arrangement by contacting GMI
3) World Christian Database (WCD), www.worldchristiandatabase.org/wcd/ Todd M. Johnson, ed., World Christian Database (Leiden/Boston: Brill, accessed November 2013.) For information regarding data access see www.wordlchristiandatabase.org/wcd/about/WCD Brochure.pdf
4) UN regions, 2013, from unstats.un.org/unsd/methods/m49/m49regin.htm
5) Mapping the Global Muslim Population, PEW Research, 2009, from www.pewforum.org/2009/10/07/mapping-the-global-muslim-population/
6) Global Christianity, A Report on the Size and Distribution of the World’s Christian Population, PEW Research, 2011, from www.pewforum.org/2011/12/19/global-christianity-exec/
7) The future of the global Muslim population, PEW Research, 2011, from www.pewforum.org/2011/01/27/the-future-of-the-global-muslim-population/