Survey about S/MIME or the use of encrypted eMails in general

Hi Everybody!

 

 

I?m due to write a software and paper for/about secure eMails. Software will
use S/MIME, but for the paper other protocols like PGP etc. are also
interesting to me?

 

Does anybody know where to find some good surveys about the use of encrypted
eMails. I think that the amount of peoples who use S/MIME, PGP etc is very
small? (smaller than 5-10% ?!?!?!)

There are some good surveys about spam, viruses etc ? but I didn?t  find
something interesting about encrypted eMails?

 

 

Thanks?

 

Jürgen