Guess which "Judeo-Christian" country has the most jihadis in Syria

No ... not Canada.  Not yet anyway.  The Canadian jihadists prefer to stay back in Canada and sue the government   for millions of dollars for putting obstacles in their way to perform the holy task of killing infidels and for being stupid enough to import them to Canada in the first place.  
The Canadian jihadists  like the smell of easy money more than the smell of infidel blood. 

Thomas Hegghammer writing at WashingtonPost:
Number of foreign fighters   from Europe in Syria is historically unprecedented. Who should be worried? 

Since 2011, large numbers of European Muslims have gone to Syria to fight with the rebels. But exactly how many are they, and which countries are providing most of the fighters? The question matters because some of these foreign fighters may return to perpetrate attacks in the West, and Western governments are now grappling with the question of how to design and calibrate countermeasures.
Assessing the terrorist threat to Europe from the foreign fighters in Syria is tricky. On the one hand, as I showed in an earlier study summarized here on the Monkey Cage, foreign fighters are much more likely to engage in international terrorism than the general Muslim population, and they produce more lethal attacks than do plotters without foreign fighting experience. On the other hand, only a small proportion of Western foreign fighters tend to come home to attack. Moreover, the return rate varies considerably between destinations; for example, Western foreign fighters in Pakistan have tended to return for plots more frequently than their counterparts in Somalia......