According to the Pew Research Center, Europe's population was 6% Muslim in 2010, and is projected to be 8% Muslim by 2030.[31] (The data do not reckon illegal imigration from the Middle East and Africa since the migration crisis.)
A Pew Research Center study, published in January 2011, forecasted an increase of Muslims in European population from 6% in 2010 to 8% in 2030.[31] The study also predicted that Muslim fertility rate in Europe would drop from 2.2 in 2010 to 2.0 in 2030. On the other hand, the non-Muslim fertility rate in Europe would increase from 1.5 in 2010 to 1.6 in 2030.[31] A Pew study published in 2015 projected that in 2050 Muslims will make up 10.2% of Europe's population.[44] Data for the rates of growth of Islam in Europe reveal that the growing number of Muslims is due primarily to immigration and higher birth rates.[45]
Philip Jenkins of Penn State University estimates that by 2100, Muslims will compose about 25% of Europe's population. Jenkins states this figure does not take account divergent birthrates amongst Europe's immigrant Christians.[46] Other analysts are skeptical about the accuracy of the claimed Muslim population growth, stating that because many European countries do not ask a person's religion on official forms or in censuses, it has been difficult to obtain accurate estimates, and arguing that there has been a decrease in Muslim fertility rates in Morocco, the Netherlands and Turkey.[47]