Housing values up 18%

The average price of homes in the Elizabeth ZIP code of 28204 went up 18% last year, the Charlote Observer reports. That's one of the highest rates of increase in the county, although far short of the 35% of 28206, north of downtown. The numbers are for June 2004 to June 2005, and include only those homes sold through the Charlotte Multiple Listing Service. I understand that not too long ago homes in Elizabeth would sell without listing. Any real estate experts know if this is true? If so, what does it mean for the data?