you'.. find it at the CDC website. "Studies show that about one in three (33%) people carry staph in their nose, usually without any illness. Two in 100 people carry MRSA. There are not data showing the total number of people who get MRSA skin infections in the community". Link:
Its very hard to say exact percentage of MRSA/MSSA globally. As some of the resource constrained hospitals (even if they are huge and have automated machines) in developing or under developed nations are not following MRSA properly. Though CDC is giving data of MRSA... but still what is the exact load globally... its hard to say.
The best way is to follow research articles so that percentage can be caught as small or large pockets.
1. Shanmugam J, Gopal R, Senthil Kumar S. Prevalence, antibiogram & characterization of S. aureus including MRSA among hospital staff, Medical students & patients from Sri Manakula Vinayagar medical college and hospital (SMVMCH), PUDUCHERRY. DSTE Project Report, India. 2009.
2. M R, D’Souza M, Kotigadde S, Saralaya K V, Kotian M S. Prevalence of Methicillin Resistant Staphylococcus aureus Carriage amongst Health Care Workers of Critical Care Units in Kasturba Medical College Hospital, Mangalore, India. Journal of Clinical and Diagnostic Research. 2013;7(12):2697-2700. doi:10.7860/JCDR/2013/5160.3735.
3. Sah P, Rijal KR, Shakhya B, Tiwari BR, Ghimire P. Nasal carriage rate of Staphylococcus aureus in hospital personnel of National Medical College and Teaching Hospital and their Antibiotic Susceptibility Pattern. JHAS.2013,3(1):21-23.
4. Agarwal L, Singh AK, Sengupta C, Agarwal A. Nasal carriage of Methicillin- and Mupirocin-resistant S. aureus among health care workers in a tertiary care hospital. Journal of Research in Pharmacy Practice. 2015;4(4):182-186. doi:10.4103/2279-042X.167046.