Various studies have investigated the extent of open access. A study published in 2010 showed that roughly 20% of the total number of peer-reviewed articles published in 2008 could be found openly accessible. Another study found that by 2010, 7.9% of all academic journals with impact factors were gold open access journals and showed a broad distribution of Gold Open Access journals throughout academic disciplines. A study of random journals from the citations indexes AHSCI, SCI and SSCI in 2013 came to the result that 88% of the journals were closed access and 12% were open access. In August 2013, a study done for the European Commission reported that 50% of a random sample of all articles published in 2011 as indexed by Scopus were freely accessible online by the end of 2012. A 2017 study by the Max Planck Society put the share of gold access articles in pure open access journals at around 13 percent of total research papers.