David W. Lewis has self-archived "The Inevitability of Open Access: Update One" in IUPUIScholarWorks.
Here's an excerpt:
This paper updates the author's 2012 article, "The Inevitability of Open Access" with recently published data. As a result it is possible to predict that Gold OA could account for 50 percent of the scholarly journal articles sometime between 2018 and 2020, and 90 percent of articles as soon as 2021 and more conservatively by 2024.
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