XIAN, CHINA - OCTOBER 26: (CHINA OUT) Visitors view architects' models of apartment blocks during the 2007 Xian Autumn Real Estate Trade Fair on October 26, 2007 in Xian of Shaanxi Province, China. The Central Bank announced at the end of September its intention to raise the mortgage deposits to 40 percent for second apartments, in an effort to cool down housing prices. (Photo by China Photos/Getty Images)