<http://schema.org/about>
"That is what the census says. Andrew Leonard in Salon notes that it is a bit misleading, that \"4.7 million are for \"seasonal use\" only, the Census tells us -- unoccupied vacation homes, in other words. 4.1 million"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.treehugger.com/sustainable-product-design/186-million-empty-houses-in-america.html>