I've never seen any actual occupancy statistics, and DVC and Disney are pretty strict about keeping that kind of information confidential.
That said, since DVC is a timehsare, it is designed to run at basically full occupancy year round. In other words, the number of points sold, when fully used, would have every unit occupied all year. However, as units will need to go down for maintenance, DVC does retain a small percentage of units that are referred to as 'breakage'. This appears to be somewhere around 3% or so of a resorts' villas. When available, 'breakage' units are available for cash reservations. Thus the design 'occupancy' is probably pushing the 97% figure.
But a number of other factors affect occupancy rates. Since members can bank/borrow points and use them in other than their regular year, or use them for other options separate from a DVC resort reservation, the total point balance of rooms can vary full occupancy up or down. If someone uses 1000 points to take the whole family on a cruise, that's 1000 points worth of DVC villas that are not used. DVC attempts to rent rooms for that equivalent number of points, thus occupancy rates would vary due to the number of members who use points outside of DVC and DVC's success in renting those equivalent rooms.
High seasons pretty much are full occupancy as reflected by the number of posts we see regarding wait lists. Also resorts that are not fully sold out will have lower occupancy until all points are sold.
Just some thoughts.