How many administrators needed per site?

[christina boyko]

A while ago, I saw a posting calling for input about how many administrators
any given site should have.  I believe the poster was going to gather the
info and publish the stats.  I never caught the results.

Well, due to "budget cutbacks", I am in danger of losing my
partner/fellow administrator.  It seems they think I'm good
enough to handle this site all by myself.  I'm flattered, but mostly,
I'm  panicked.  I don't think that this is a 1-person job. (I have
~50 Suns on site and ~15 PC's)

So to justify my partner's existance, I need to know:
 What's the average administrator-to-machine ratio?
   
 1:20, 1:50, 1:100? (This assumes that the users do absolutely
 no administrative tasks.---They don't even have root access.)
(My personal feeling is 1:25 at most, but management thinks 1:60....)
 
 How about the average administrator-to-USER ratio. Is it different
 from admin:machine?
 
 If anyone remembers the posting I'm referring to and can
 recall the stats, please let me know. I'm also willing to
 accept input and compile the info myself. Either
 post, of better still, send me email.  I appreciate any
 help I can get. 
 
 Thanks again,
 
 Christina Boyko
 System Administrator
 rastro!boyko at uunet.UU.NET