The Government of the Netherlands has released Bibliometric Study on Dutch Open Access.
Here's an excerpt:
In this text we will primarily focus on the way Open Access (OA from now on) publications are represented in the Web of Science database. We have collected data for this analysis in two different ways, which leads to different perspectives on OA publishing in the Netherlands. We focus on the output of three smaller scientific nations in Europe, next to the Netherlands we focus on Denmark and Switzerland, as these countries do contest the scientific runner up positions globally after the USA, and are more or less of comparable volume in economic terms.