Judging by all the commercials for cleaning products, it's not clear that marketing people have caught up with this one, but households headed up by married people are no longer in the majority. This information comes to us courtesy of the most recent Census figures, which have been trickling out this year and are supported by a bunch of other studies. Wedlock is barely a minority, though: in 2005 49.7%, or 55.2 million, of the nation's 111.1 million households were headed by married people, according to the American Community Survey. Five years earlier, the number was 52%. The other 50.3% is made up of unmarried couples, people living alone and, increasingly, homes headed by a single parent.