I imagine it varies widely by location and size of the congregation.
On the other hand, many rural Catholic parishes share a priest.
The Diocese of Superior, WI, which covers most of Northwest Wisconsin, is a prime example.
They've had a priest shortage up there for years. My parents had a home in Solon Springs, WI, about 35 miles south of Superior. There were sister parishes in Gordon and Minong, WI. Between the three parishes, which from top to bottom are about 22 miles apart, they had one priest who said Mass at all three parishes.
Rural Douglas and Washburn Counties are typical of the problems rural priests face -- lots of distance and modest amounts of Catholics whose spiritual needs are just as important as city dwelling Catholics. That's going to lead to burnout, as Brother Legs pointed out for Oak Park.
In Superior itself, most of the parishes, including the Cathedral of Christ the King, share priests with other Catholic congregations.