CrossRef Indicators
The latest stats on CrossRef activity have been posted at
http://www.crossref.org/01company/crossref_indicators.html
CROSSREF INDICATORS (September 22, 2006)
Total no. participating publishers & societies 1,680
% of non-profit publishers 64%
Total no. participating libraries 1,103
No. journals covered 15,193
No. DOIs registered to date 22,515,600
No. DOIs deposited in previous month 294,257
No. DOIs retrieved (matched references) in previous month 4,503,094
DOI resolutions (end-user clicks) in previous month 11,007,980