In my last post, I noted that fighters per Muslim is arguably a more appropriate measure of the number of fighters a country has sent to Syria and Iraq than simply fighters per capita. The table below gives fighters per Muslim for all the countries included in the ICSR dataset; countries are ordered from highest to lowest. Western European countries are noticeably over-repented at the top of both lists. Overall, the number of fighters per Muslim from Western European countries is about 5 times higher than the number of fighters per Muslim from non-Western European countries, and is approximately 2.3 times higher the number of fighters per Muslim from all countries together.
Possible explanations for the over-representation of Western European countries at the top of these lists include the following. The figures are inaccurate; many of the fighters from Western European countries are not Muslims; many fighters from non-Western European countries have gone to places such as Libya or Yemen instead; Western European Muslims are richer and so can more easily afford to travel internationally; Western European Muslims are more radicalised; jihadist groups and rebel groups have been disproportionately targeting Western European Muslims; the relatively free press in Western Europe has given prospective fighters greater access to recruitment materials; Western European governments have been less stringent in interdicting those trying to leave.