Business Week reports in its Feb. 13 edition that the changing demographics of the U.S. population may adversely impact car and truck sales in the years ahead. Citing a Federal Reserve Bank of Chicago study, BW says that between 1970 and 1992 more than 32 million households were formed, but that the share of married couples shrank to 53% from 77%. "At the same time, the shares of one-parent and single-person households jumped 16% and 31%, respectively," the magazine reports, adding that "these changes spell increasing income inequality." What does all of this mean? The study shows single parents' spending was only 29% that of married folks in 1992, and that outlays by single persons were running at 56% of those of the married group. This "startling growth of non-traditional households," says BW, portends an "adverse impact on purchases of big-ticket items like cars."