Thanks for the link, AL. This report has been the subject of some recent contention. Although CSIS estimates that only about 12% of insurgents in Iraq are foreigners, this past week several statements were made by Iraqi security officials claiming that 90% of the suicide bombers are foreigners, mostly of Saudi origin. I'll look for a link to the source of those statements, but in the meantime it seems that
1. CSIS does not have an incentive to falsify statistics (or the reputation for ever having done so), while Iraq's officials would clearly benefit from placing blame outside of their own sphere of influence.
2. Perhaps both are right. While the insurgency's main corpus may be composed of Iraqis, it may be the case that the most violent attacks depend on a supply of foreign volunteers.
I'd be interested in hearing how others would square these two conflicting sets of claims...