In the 5 years we have been
DVC owners, rack rates have consistently gone up 3-5% per year. The exact number varies depending on resort, room class and season. But 3% is pretty much the minimum.
But as others pointed out, it's more complicated than that. Over the last 3-4 years, Disney hasn't been nearly as generous with discounts as they were in the years immediately following 9/11. There was a time when AP discounts could run 40% off of the rack rates. Now folks are lucky to get around 15% off.
Spend too much time looking at those numbers and it will make your head spin.
I think a good rule to remember is this: DVC dues are tied to actual operating costs. As prices inflate (salaries, fuel for buses, insurance premiums), so will our dues. In that sense we have the advantage since the increases are not subject to Disney whim.
Cash prices are a little more volatile. When the economy is going good and occupancy is high, Disney could decide that they want to force a 5% increase. Of course, the other side to that is when the economy is bad, Disney could decide to eat some profits in a given year and hold rates steady or only have a nominal increase. But (and this is the big "but"), such actions would be motivated purely by short-term needs. Even if Disney should implement a less-than-expected rack rate increase some year, you can bet your last dollar that they will make up for it later. In the long-run, Disney isn't going to allow room rates to run behind cost-of-living increases required to operate the resorts.