The Pew study also projects that, based on current immigration levels and extrapolations from birth rate trends, the Muslim population in Europe by 2030 will be 29.8 million, or 7.1 percent of the population.

QUESTION: Projections depend on current immigration levels and birth-rate extrapolations; worth noting how sensitive these figures are to policy and demographic shifts.

Green, Todd H, The Fear of Islam_ An Intro…, loc. 339