Another day, another report about the continuing decline in residential real estate prices -- but at least one tinged with the kind of optimism that comes when things aren't getting as bad as fast as before. According to the real estate web site Zillow.com, which tracks home sales prices and tries its Zillow best to estimate how much homes not on the market would fetch, the value of U.S. homes fell 12.1 percent in 2Q09 compared with 2Q08, just before the panic set in.