Dramatic Growth Of Open Access 2013 First Quarter: Comparisons

Update April 5, 2013: Dirk Pieper of the Bielefeld Academic Search Engine reports on the BASE new OA designation (from the GOAL Open Access list). BASE has been able to confirm:

we can indicate 11.320.432 out of 43.713.380 documents almost certainly as OA. In result lists you will see the small OA symbol if a document is OA, in addition you can refine your result list to OA results only.

This 25% should be regarded as a minimum as not every repository is able to report OA contents to the BASE search harvester.  Repository managers please see the GOAL list post for information on how to make OA information for contents in your repository available.

Second corrections: the title of this post has been changed to 2013 from 3013 to reflect the correct milennium, and the w in HighWire is now capitalized throughout...