A significant percentage of the population (30-40%) are asymptomatic carriers of S. aureus, drug sensitive staphylococcus aureus
and 1%-5% of individuals in the community are colonized with MRSA. Multi drug resistant staph aureus.
http://www.mrsaid.com/for-clinicians/
A 1%
If question is about carrier percent of simple staph aureus 30_40%
Nasal carriage rates are 25–50% in the general population is a major cause of skin and surgical-site infections, and is one of the most common causes of healthcare-associated infections. therefore , 25% is a right answer