Just to add on to hornetguy...
Almost every squad I know has Training and MWR clerks, plus element NCOs. Like hornet said, the rest are squad dependent. In my squad, for almost every NCO position that a 2-dig has, their is a clerk for that same job. Plus, a lot of us have more than one job. Personally, I've had a lot more stuff to do has a Public Affairs Clerk than as an Element NCO.