Info on I-Series standing

In trying to dissuade mgmt thinking of OS400 as an old and fading
technology, I have been looking for information or  figures on the
percentage of total I.S.
dollars spent for AS/400 I-Series hardware and software, vs. other
platforms. 
 
  For example,   28 % spent on NT:   35 % on Unix;  15 % on OS390;  8 %
OS400 .  (As a % of total I.S.  budget)  
You get the idea.

   The thought process I am dealing with , is that AS/400 is on the backside
of the technology bell curve.
   I have searched IBM, sites and many others but have had little
success......
I would also be interested any  articles, links  , charts , etc  - that have
information on any of the following:

        * percentage Fortune 500 companies utilizing AS/400's in some form
        * total number of AS/400's sold :(upwards of 600K , last time I
read)
        * Sales numbers VRS . other platforms.          
  I would like to be able to show, from an independent source, that AS/400
is holding it's market share.  
( I hope that is the case )  

        All responses appreciated.

Ellis Hankins
Ralston Purina Co
314 982 2785
ehankins@purina.com