SAN FRANCISCO -- We've now seen the upside to having an industry sector lose half its market value in six months.Once you get around to the really bad news, you may have gone as low as you can go. The trade group Semiconductor Industry Association said Monday that worldwide chip sales in January fell 28.6% to $15.3 billion from $21.5 billion a year earlier. Sales also were off 11.9% from December. "Worldwide semiconductor sales in January, historically a relatively weak month for the industry, reflected a continuing erosion of consumer confidence and the effects of the global economic recession," said SIA President George Scalise in a press release. "Sales declined across the entire range of semiconductor products, as sales of important demand drivers such as personal computers, cell phones, automobiles and consumer items remained under pressure. As has been the case with overall industrial demand, the SIA's latest numbers merely indicate the speed of decline that happened at the end of 2008. Going back to October, year-over-year monthly chip sales fell, in succession, 2.4%, 9.8%, 22%, and now 28.6%. The SIA, which isn't in the business to thrust bad news into the light, was similarly caught off guard. In November, the trade group had expected global sales would fall just 2.2% in 2008. Two months later, the reality was that sales came up nearly $13 billion short of expectations. The story remains the same: A huge buildup in inventory has combined with the slowdown in demand for the main consumer items that drive semiconductor growth -- PCs, telecom handsets, and automobiles.