Hollywood Blacklist Question:

I've read quite a bit about the Hollywood blacklist lately, but the answer to an obvious question has been surprisingly elusive: what percentage of those blacklisted were members of the Communist Party of the United States at the time of their blacklisting? A secondary question is, of those who weren't members of the CPUSA at the time of their blacklisting, why (a) did they wind up on the blacklist; and (b) did they not "clear their names" and get off the blacklist (I know some did, but I'm talking about those who didn't).

I've opened comments, but I really don't want to open a debate on the morality, wisdom, etc. of the blacklist--perhaps we can have one after I finally post my review of Redish's The Logic of Persecution. Rather, I'd like informed answers, preferably with sources, to either or both of the questions above.

UPDATE: An expert on the subject emails (didn't get his permission yet to use his name) to estimate "98 per cent, and the other two per cent had been and may have left its ranks by that time." If anyone has contrary information, please let me know.