There have been bad housing markets before, but never in post-World War II history has the market for new homes suffered as badly as it has in this decline. That plunge raises questions about whether some homes built during the boom will ever be sold. It could also suggest that home builders have been slow to cut their prices enough to keep up with falling market prices. For more than three decades, the sales volume of existing single-family homes and newly built houses tended to rise and fall by about the same percentage. To be sure, sales of new homes did tend to do a little worse during recessions, but the difference was small and short-lived. At the peak of the housing boom in 2005, sales of both existing and new homes were running at twice the 1976 rate. This year, the sales rate for existing homes seems to have stabilized at about one-third higher than the 1976 rate. New-home sales also seem to have stabilized, but at about half the 1976 rate. The plunge in sales of existing homes is severe but not unprecedented. But new-home sales are now running at only about a quarter of peak levels, a fall far deeper than anything seen since the statistics began being collected in the 1960s. New-home prices, while they have fallen sharply, do not appear to have declined as far as prices of existing homes. At the worst point this year, the median price of existing homes was off 29 percent from the peak, while the largest drop for new-home prices was 23 percent. Median home price figures need to be used with caution, since there is no way to know how the median home sold in one month compares, in terms of size and location, to the median home sold in a different month. But in past recessions, new-home prices have tended to be weaker than existing-home prices, the opposite of what has happened in this cycle. 'Foreclosed homes are the supply that has to be worked off,' said Robert Barbera, the chief economist of ITG, an investment advisory firm. He said the problem had worsened in recent months after the end of the foreclosure moratorium adopted by many lenders while they waited to see what the Obama administration would propose. Of the 135,000 completed but unsold new homes at the end of May, nearly half had been sitting for a year or more. The median age of such homes was 11.5 months, an unprecedented figure. It may be that builders will have to cut prices even more to sell some houses -- houses that, in retrospect, probably should never have been built at all. 