mean and median number of citations per article?

[Karen A. Robinson]

I'm looking for the mean and median number of citations per article. 
Ideally, for overall and also for clinical trials in specific. I've seen 
a number of different figures but thought someone on this list would 
know of the definitive source for this information. Also of interest 
would be the number or proportion of articles that remain uncited. I 
recall seeing a figure, I think from Garfield, that gave this at 25%.

thanks in advance for your suggestions and advice,
Karen
-- 
Karen A. Robinson
Internal Medicine and Health Sciences Informatics, Medicine
Johns Hopkins University
1830 East Monument Street, Room 8069
Baltimore, MD 21287
410-502-9216 (voice)
410-955-0825 (fax)
krobin at jhmi.edu