According to a BBC online article dated the 25/10/13, there were a total of:
"...scores of Europeans who have travelled to Syria in the last few years. Various estimates put the figure at 500-600."
I did some searching on the WWW and came up with these figures from various press and organisational sites: does it only add to 600? NO. In fact, more, a lot more.
These graphs are an approximate snapshot of the numbers per country, (mostly from the West or non-Islamic in nature). The information is based on stated figures in a wide range of media articles, as well as reports on the issue. If anyone has other figures then please let me know.