MIAMI (CBS4) – America’s housing bubble went bust when the mortgage mess began.

Since then, a wave of foreclosures and high unemployment have led to sluggish sales nationwide.

Now the National Association of Realtors says those sale figures are about to get  even worse.  The group is revising its national sales numbers downward.

“The model they used for calculating existing home sales have diverged from the actual market,” said Realtor Ralph De Martino.

Why all the changes?

Because those national numbers aren’t based on actual sales, they’re based on statistics.

Population shifts during the last decade affected individual regions, and affected the statistics.

And some sales were counted twice, if they appeared in the listings of two near-by areas.

But De Martino said South Florida’s sales numbers won’t change because they’re based on old-fashioned counting.

“The local associations have the numbers exactly,” said De Martino. “They’re not using any kind of models.”

He also said our median home prices are rising, and so are sales.

“The bottom’s already happened, but on the way up, so it’s a great time to buy,” said De Martino.