There was a thread here a while ago about core and sheath strengths. It got me curious, so I asked the owner of BlueWater for some data on their Canyon and Canyon Pro ropes.
Canyon Pro gets virtually 100% of its strength from the core. This is due to the fact that the Spectra core doesn’t stretch much compared to the polyester sheath.
Canyon rope gets 76.56% of its strength from the core. Nylon core, polyester sheath.