Volume and Open Interest data

I'm looking to find volume and open interest data for several over-the-counter commodities. Does anyone know where to look?

 

http://www.cmegroup.com/market-data/datamine-historical-data/volume-open-interest.html

 

Thanks for that but the CME data is only for exchange listed securities. I'm specifically looking for OTC volume and OI figures.

 

What OTC commodities are you referring to?