From QDMA:

That depends on a buck’s age, and older bucks make more rubs. According to the University of Georgia’s Dr. Karl V. Miller, one mature buck can make 1,000 to 1,200 rubs per year. Considering most rub activity occurs over a 3-month span that would be 10 to 15 per day. So in an area where the deer has an older age structure and a balanced sex ratio, bucks can produce over 3,000 rubs per square mile.

Contrast this to a deer herd with a young buck age structure. There, yearling bucks will make less than half as many rubs, so you may only have 400 to 500 rubs per square mile.

By the way, yearling bucks make only about 15 percent as many scrapes as older bucks do.