A look at the dues history of OKW (the oldest DVC resort), shows an average increase of 3.6 percent a year. Here are the percentage increases by year:

1992 2
1993 2.7
1994 2.6
1995 5.1
1996 5.2
1997 5
1998 1
1999 -.03
2000 0
2001 -1
2002 2.8
2003 8.3
2004 5.4
2005 4.9
2006 9.8
2007 3.7
2008 3.6
2009 3.7

Obviously there were a couple of big jumps, and a couple of years when dues actually went down, but I couldn't tell you the reasons. Maybe an OKW owner can.