i heard the other day (on the cbc) that there's 4.5 million muslims in switzerland (which is kinda like part of austria, right?)
i took note of it, because it seemed unlikely
turns out there's less than 0.4 million muslims, or 4.5% of the overall population
I think it might be more accurate to say that parts of Austria are like Switzerland, but saying Switzerland is kind of like part of Austria might be silly when Switzerland and Austria have roughly the same population.
And yeah, 4.5 million would mean more than half of the population of Switzerland. It hasn't come to that quite yet.

Germany probably has somewhere around 4.5 million muslims thanks in part to all the people who moved there from Turkey after World War 2. But Germany's total population is more than 80 million.
I think this excerpt from the Wikipedia article about Sweden pretty accurately describes the situation with Islam and muslims in most European countries:
The first Muslim congregation was established in 1949 when a small contingent of Tatars migrated from Finland, but Islam's presence in Sweden remained marginal until the 1960s when Sweden started to receive migrants from the Balkans and Turkey. Further immigration from North Africa and the Middle East have brought the estimated Muslim population to 500,000. However, only about 110,000 are members of a congregation and of these approximately 25,000 actively practise Islam in the sense that they pray five times a day and attend Friday prayer.
Fears that Europe will be overrun by Islam are a bit overblown. It's more that, if Europeans had been truer to our heritage, these immigrants from Islamic countries would be gradually adopting Christianity rather than becoming spiritually indifferent and only nominally religious.