A new and comprehensive demographic study of more than 200 countries, finds that there are 1.57 billion Muslims of all ages living in the world today, representing 23 per cent of an estimated 2009 world population of 6.8 billion.
Released by the Pew Research Center's Forum on Religion & Public Life, 'Mapping the Global Muslim Population' offers the most up-to-date and fully sourced estimates of the size and distribution of the worldwide Muslim population, including particularist identity.
Key findings from the survey are that:
* While Muslims are found on all five inhabited continents, more than 60 per cent of the global Muslim population is in Asia and about 20 per cent is in the Middle East and North Africa.
* The Middle East-North Africa region has the highest percentage of Muslim-majority countries. More than half of the 20 countries and territories in that region have populations that are approximately 95 per cent Muslim or greater.
* More than 300 million Muslims, or one-fifth of the world's Muslim population, live in countries where Islam is not the majority religion. These minority Muslim populations are often quite large. India, for example, has the third-largest population of Muslims worldwide. China has more Muslims than Syria, while Russia is home to more Muslims than Jordan and Libya combined.
* Of the total Muslim population, 10-13 per cent are Shia Muslims and 87-90 per cent are Sunni Muslims. Most Shias (between 68 per cent and 80 per cent) live in just four countries: Iran, Pakistan, India and Iraq.
Previously published estimates of the size of the global Muslim population have ranged from 1 billion to 1.8 billion. The new study is based on the best available data for 232 countries and territories.
Pew Forum researchers, in consultation with nearly 50 demographers and social scientists at universities and research centres around the world, analysed about 1,500 sources, including census reports, demographic studies and general population surveys, to arrive at these figures - the largest project of its kind to date.
The report includes an executive summary, maps and charts illustrating the geographic distribution of Muslims, explanations of the study's methodologies and a list of data sources by country. It is available online at: http://pewforum.org/docs/?DocID=450 
The findings on the world Muslim population lay the foundation for a forthcoming study by the Pew Forum, scheduled to be released in 2010, which will estimate growth rates among Muslim populations worldwide and project Muslim populations into the future.
The Pew Forum plans to undertake similar demographic studies of the major global religions in the future.
The Pew Research Center's Forum on Religion & Public Life aims to deliver "timely, impartial information on issues at the intersection of religion and public affairs. The Pew Forum is a nonpartisan, nonadvocacy organization and does not take positions on policy debates."
Based in Washington DC, USA, the Pew Forum is a project of the Pew Research Center, which is funded by The Pew Charitable Trusts.