Anatomy of open access publishing: a study of longitudinal development and internal structure

Table 2 Proportion of publisher-provided (gold) open access in major indexes

Articles indexed in Scopus	2008	2009	2010	2011
Total^a	1,469,286	1,550,413	1,588,636	1,658,643
In full immediate OA journals^b	118,751	133,817	163,670	181,706
Share of articles published in full immediate OA journals	8.1%	8.6%	10.3%	11%
Hybrid OA^c	4,718	8,095	10,135	12,089
Delayed OA^d	78,054	82,271	81,404	85,714
Total share OA	13.7%	14.5%	16.1%	16.9%
Articles indexed in Web of Knowledge	2008	2009	2010	2011
Total^e	1,154,803	1,203,692	1,235,202	1,294,051
In full immediate OA journals^b	76,537	85,852	103,514	116,192
Share of articles published in full immediate OA journals	6.6%	7.1%	8.4%	9.0%
Hybrid OA^c	3774	6476	8108	9671
Delayed OA^d	76,076	80,338	79,058	83,420
Total share OA	13.5%	14.3%	15.4%	16.2%

^aAll articles + reviews, retrieved 22 May 2012 through scopus.com; ^bresults of this study; ^cresults of previous research [8]; ^dresults of an ongoing study by the authors, based on absolute volume calculations for articles in 462 unique journals available through HighWire Press, PubMed Central, Elsevier and so on with an open access delay of 12 months or less; ^eall articles + reviews included in the Science Citation Index Expanded, Social Sciences Citation Index, Arts & Humanities Citation Index, retrieved 22 May 2012 through apps.webofknowledge.com. OA: open access.

ISSN: 1741-7015