With the release of version 2.11 of the OS dataset, we can update our reporting on adoption rates for open educational resources (OERs) — specifically, open textbooks and ‘open access’ monographs. We track OER adoption via the appearance of titles on syllabi — the point of use rather than the point of sale or distribution. In 2013, OER textbooks were barely on the scene and used in only around 1 in 400 classes. By 2023, it was 1 in 80. Over the past 10 years, the growth rate in OER textbook use has averaged around 17.5% per year in the US.