How many Muslims are there?

I've put this on to http://www.vexen.co.uk/religion/islam.html :

• 44 countries are over 50% Muslim.
• 1.6 billion Muslims in 2010 (23.4% of the world): 2.2 billion by 2030 (26.4%)
• 6% of Europe was Muslim, in 2011. Will rise to 8% in 2030
• 2.7% of the population of England & Wales are Muslims (and rising)

Population growth in the world is highest amongst the poor and the uneducated. Muslims have a disproportionate share of such people, so their numbers are rising. Factors such as war and instability in the Middle East keep the reproduction rate higher.

The Muslim world is slowly aging. "In 1990 Islam's share of the world's youth was 20%; in 2010, 26%. In 2030 it will be 29% (of 15-29-year-olds)". But on average, Muslims are starting to age. "The media age in Muslim-majority countries was 19 in 1990. It is 24 now, and will be 30 by 2030. (For French, Germans and Japanese the figure is 40 or over.) This suggests Muslim numbers will ultimately stop climbing, but later than the rest of the population".