the future of libraries in the digital age
Wiley Author Survey on Open Access Access 2012:
Out of the 10,673 respondents, 32% had already published in an open access journal, defined as "free for all to read, download and share online and the author, their institution or funding body pays a fee to ensure that the article is made open access. The highest proportion of open access authors came from a medical background (28%), closely followed by biological sciences (24%)".
I find these discipline-related differences intriguing...