The muslim invasions costs? $86 Billion and counting.

Germany Puts Migration-Related Costs at Over $86 Billion Over Next Four Years

But they will work, and pay this back through taxes.

"A recent study in Denmark pinpointed that, of the full range of backgrounds of migrants who had settled there, Syrians had the lowest levels of employment of all (22.8%). A separate longitudinal study from Denmark also showed that, of those Muslim migrants who had come to Denmark claiming to be refugees: only one in four had actually succeeded in finding a job after a decade."

The True Cost of Europe's Muslim "Enrichment"

Even among muslim citizens of Britain only half the men, and 25% of the women work, and pay taxes. Ooofdah!

OK, so, 20-25% will work and pay $86,000,000,000 back through taxes! There are 1,000,000 muslim vacationers, er, immigrants now decamped in Europe. So, 25% would be 250,000 divide $86,000,000,000 and you get $344,000 per person. They should be able to pay that off shortly, right?

The data seems to show most muslims in low wage jobs, and it seems likely that the highest paid muslims would be muslims native to Europe from wealthier homes, and well educated.

The Muslim effect on immigrant integration in France

These people will never be able to pay back this huge sum of money, and Europe will never see an economic benefit from this migration. Even if the integration is a good as Britain's integration of muslims, still muslim's dismally high unemployment rates, and low workforce participation rates mean the second, third, and later generations will never catch up to these costs. In essence, Europe is permanently shedding wealth to allow these people to immigrate. This seems a bad idea. 

Worse, how much more will the costs rise after the first 4 years? Disaster!