"experienced an average of" is correct and usable in written English.
You can use it to describe a situation in which someone has been through a certain amount of something over a certain period of time. For example, "The company experienced an average of 500 new customer inquiries per month over the past year."
Until 2008, Oklahoma experienced an average of one to two earthquakes of 3.0 magnitude or greater each year.
Those who were not treated with the vaccine, however, experienced an average of about 1.6 months of progression-free survival.
Her research, presented in September to the British Association of Sports and Exercise Sciences, found that women experienced an average of about four inches of total breast movement, and some experienced more than double that amount.
A 2001 study in The Annals of Emergency Medicine found that emergency room doctors experienced an average of 10 interruptions an hour, compared with 4 an hour for primary care doctors.
A study published this spring gives some hint of the relentlessness with which this message is conveyed, especially to overweight women, who experienced an average of three rude comments or behaviors about their size per day.
The UK as a whole experienced an average of 121 hours of sunshine in March - compared with a norm of 97 hours for the month and a figure of only 52.5 for February.
The city has an average annual precipitation of about 10 inches (230 mm) and experiences an average of 48 days of frost per year.
It is expensive: according to the Ponemon Institute, an outfit which researches digital matters, organisations experience an average of 122 successful attacks a week, which take an average time to resolve of 32 days at a cost of $32,469 a day.
In a region where there is an annual average of five strikes per square kilometre, the same building will experience an average of 0.0058 direct strike per year, or one strike about every 174 years.
In a region where an average of three cloud-to-ground lightning strikes occur per square kilometre annually, such a building will experience an average of 0.0035 direct strike per year, or one strike about every 290 years (1,152 square metres × 3 flashes per square kilometre × 10−6 metres per square kilometre).
