ECC memory percentage?

Hello,

I am looking for the percentage of GDDR5 memory used when ECC is activated on Xeon Phi to check that the result of micinfo (GDDR Size) is correct.

I've read 12.5% (1 bit per byte), 3.125%, and observed 3.125% (32MB per GB).

Where can I find this information? (I did not find it on the specification of the different Xeon Phi models)

Thanks,