From a few years ago...2 years
"As many as 1,000 Turks have joined ISIS, according to Turkish news media reports and government officials here. Recruits cite the group’s ideological appeal to disaffected youths as well as the money it pays fighters from its flush coffers. The C.I.A. estimated last week that the group had from 20,000 to 31,500 fighters in Iraq and Syria."
https://www.nytimes.com/2014/09/16/w...uits.html?_r=0