Number and/or total size of CC-0 datasets. Source: BASE. https://www.base-search.net/Se...

Number of OAI-compliant repositories. Source: BASE content sources. https://www.base-search.net/ab...

Number of repositories with an open data (https://opendefinition.org/ ) policy for metadata. Source: OpenDOAR, "commercial" in metadata reuse policy. https://opendefinition.org/

Number of datasets issues with a DOI and where they cited. I think trying to capture how/where data is reused is of more impactful then just monitoring the number of repositories.

1) Number of downloads from data repositories 2) Number of CC0 policies associated to datasets

Number of papers on reporting research reusing existing data sets

Number of papers based on openly available (raw) data

Number/share of papers having an statement on data availability

Additions of new data/datasets to data repositories, by field

Openly avialable datasets, by license