Laakso M, Welling P, Bukvova H et al. The development of Open Access Journal Publishing from 1993 to 2009. PLoS ONE 2011;6(6):e20961
Results of a study on the development of open access (OA) journals, registered in the Directory of Open Access Journals (DOAJ), showed a very rapid growth in the period 1993-2009. Since 2000 the average annual growth rate has been 18% for the number of journals and 30% for the number of articles. The volume of OA published peer reviewed research articles has grown at a much faster rate than the increase in total volume of all peer reviewed research articles. Three major phases of OA development are suggested: the Pioneering years (1993-1999), the Innovation years (2000-2004), and the Consolidation years (2005-2009).