at least 3 million too many empty housing units in the country. This number, moreover, is rising ...

It's Only Going to Get Worse Everything you always wanted to know about the housing crash, but were afraid to ask. | by Lawrence B. Lindsey | 06/09/2008,
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There are 129 million housing units in the United States, comprising owner-occupied, rented, and vacant units. Of these, 18.5 million are empty. This vacancy rate is 2.5 percentage points higher than it has been at any point in the half century the data have been tracked, translating into at least 3 million too many empty housing units in the country. This number, moreover, is rising. This is the most intractable part of the real estate bubble, for we cannot find a true bottom to home prices until this inventory of empty units starts to clear, and we cannot find a bottom to the mortgage finance market until home prices bottom out. ...