The Open Access (OA) model for scientific publications has been examined for years by academics who have argued that it presents advantages in increasing accessibility and, consequently, in increasing the impact of papers. It has been noted that OA availability has increased steadily over the years. However, current measurement has seriously underestimated the proportion of OA peer-reviewed
... [Show full abstract] articles. This paper presents the results of a pilot study that shows evidence that the proportion of measured OA is so close to 50% that we have most likely passed the tipping point, that is, the stage where the majority of articles become available for free.