CBS: IED Attacks Decrease Dramatically

EFP's are different from IEDs.

An IED can be made from anything, cobbled together in any way to blow up. Anybody can build them.

An EFP requires some highly technical knowledge and skills. It has to be made just-so, to certain scientific specifications, or it won't work. That requires a precision of manufacture which is beyond the capabilities of your average garden variety jihadist.

Explosively Formed Projectiles
http://www.afrlhorizons.com/Briefs/Dec04/MN0407.html