Pl provide reliable statistics to prove the oft-cited claim that Islam
is the fastest growing religion.

I don't think, there is enough statistics to prove that Islam is the
fastest growing religion - I am sure there is some religion somewhere
- probably started with 1 member last year, and has tripled or
quadrupled its numbers in one year ;-)

But as far as major religions are concerned, Islam is considered the
fastest growing religion.  According to

http://www.religioustolerance.org/growth_isl_chr.htm

U.S. Center for World Mission claims the rate of growth to be 2.9% for
Islam and 2.3% for Christianity.

Hope this helps!

I have read statistics that have proven Islam to be the fastest
religion, and i have seen others that have said its Chrisitanity. Most
statistics go towards Islam. However, because of the controversy, its
very difficult to understand which one is the largest. Anyway,
population doesn't matter because Islam is growing fast because of its
high birth rates in South Asia and Africa, and Christianity is growing
because of its high birthrates in Latin America and Africa. So a
better question is- which one has more converts? But there is no
reliable source on this (as far as ive seen).