But they have not collapsed in the developing countries...in Europe their BRs are much higher than the national population...check out the muzzie BRs in Spain, England, (most popular boys name...mohammed).
That is the problem...European national BRs are below the 2.1 rate while the muzzies are breeding like flies...or roaches.
I think you mean in the developed countries?
In either case, you are still wrong. Data is slightly harder to come by, when referring to subpopulations, but the birth rate among North Africans in France — a fairly good proxy for religion, since most French Muslims are from France’s North African colonies — is less than 2.4. That’s marginally higher than France’s native (”cosmopolitan”) population (1.9), but not enough to skew anything crazily.
And yes, Mohammed is England’s #1 boy’s name, but that’s because it accounts for a third of all Muslims, whereas the most common boy’s names among everyone else accounts for less than 1% of the population. The days of everyone being named Joseph, Harry or George are long gone.