I need some industry data that shows what typical headcount ratios are
between a sustained engineering team and new engineering team in
software companies.  If industry data doesn't exist, I would settle
for information on a couple of companies (Google, Microsoft, IBM and
big ones) then smaller ones as well.

*What I've Done*
- I've found this: http://www.phptr.com/articles/article.asp?p=23953&seqNum=1&rl=1
- I've ordered the book The Build Master:
://www.google.com/search?sourceid=navclient&ie=UTF-8&rls=GGIC,GGIC:2006-16,GGIC:en&q=build+master+microsoft

*What I don't want*
- I don't want anything about startsup and dot coms.
- I don't want:  "Everyone does what is right for their business" -
this is always true, I want more analysis than that

Thanks,
Dan