I agree with Perplex. It has a role, but it's definitely not a huge role. I wouldn't be hanging your hat on it. You can't - hospitals keep that information close to their chest. Only some hospitals release any form of breakdown (Eastern did last year - InternZ score as 70%, the clinical referees 18%, the non-clinical referee 4%, the cover letter 4%, and the CV 4%), and even then they were reasonably broad and mentioned "CV" rather than the breakdown of the CV.