“Assigning Creative Commons Licenses to Research Metadata: Issues and Cases”, 19th September 2016…

“From a recent analysis, out of a sample of around 2500 publication repository services in OpenDOAR 2 ([those] supporting the OAI-PMH protocol standard), only 9 expose metadata license information: 3 with CC-0, 2 with CC-BY, and 4 which require a permission for commercial use, 3 with CC-0 and 1 with CC-BY.”

Nine. Not nine percent, just… nine. And one can assume that the other 1,100 repositories in OpenDOAR are even less likely to host CC license information for metadata in some form or other.