This is a good paper that gives an overview of MRSA related stats: StatPearls - Methicillin-Resistant Staphylococcus aureus.

The answer is it depends. It's about 23.5% worldwide if I recall correctly, though I'm having trouble finding the paper I originally pulled that figure from. The paper linked puts it around 30-40%. Keep in mind that MRSA is pretty prevalent, so most people who have it have a commensal "infection" that just hangs out on their skin and, even if it does become pathogenic, it's often subclinical, so many of the less serious cases go unreported. It's only when it's pretty bad or when people are undergoing medical treatment already that it's actually discovered and even then often not in a way that can be reported. On top of this, treatment varies depending on numerous factors, so areas with fewer medical resources will have significantly higher mortality rates.