The performance tables for KS4 do not mention private schools - they list "England - schools" and "England - state funded schools only". But by taking the difference we can work out that 60813 pupils at private schools achieved 23176 EBaccs, a pass rate of 38%.
To be fair, when students started their courses two years ago no one knew that this qualification would exist. Against this, the EBacc was thought to favour private schools which, typically, select pupils by academic ability.
I must admit I expected this figure to be higher.