CLARKONOMICS: Mortgage rates are up slightly over the past week, a phenomenon that's been entirely demand driven as people rushed to get in on historic low rates.

The average 30-year loan is now going for 4.8 percent and the average 15-year loan is at 4.3 percent -- based on credit and closing costs, if applicable.

Rates remain low because the feds have propped up the mortgage market and driven rates down to support a recovery.

In other housing news, new data from Zillow.com shows that the extreme slide in housing prices seems to be over. In fact, housing is now back to prices similar to 2004. So if you bought at the beginning of the decade, you might today eke out some gain when selling. But those who bought mid-decade may still be upside down.

The overall underpinnings for a recovery are in place. But the recovery needs three additional factors to make it a reality. First, we need to see more jobs. Second, we need to cycle through all the foreclosures. Third, we need natural housing formation to deal with the excess supply.

The Wall Street Journal published new figures from ZipRealty.com that show the number of houses for sale in many metro area has declined. It seems a lot of sellers have been on a seller's strike. Those who didn't have to sell are waiting for a recovery.

But hear Clark's words now: The firming up of prices will be very slow. Don't expect a big ratchet up in price in the next few years. It will be a gradual process.