The real estate downturn is nowhere near over, say savvy economists and followers of the industry. And San Diego's plight is among the nation's worst. According to Case-Shiller data, San Diego prices are plunging at a 31.5 percent annual rate now ( based on the last three months). Among 20 cities, only Las Vegas (dropping at 36.8 percent), Phoenix (35.2) and Los Angeles (34.6) are worse. San Francisco is tied at 31.5. Economist David Rosenberg of Merrill Lynch says that although the Federal Reserve has dropped short term interest rates by three percentage points, long term rates, including mortgages, have dropped only one-half of one percent, or one-fifth the sharp decline of short rates. The government is now forcing government-sponsored enterprises such as Fannie Mae to buy more mortgages, but that still won't do it. Before long, taxpayers will be picking up the tab for mortgages in distress, but that won't be much help, either, says Rosenberg. "Home prices are at least 20 to 25 percent overvalued," he says. (San Diego's have already gone down 21 percent from the November 2005 peak.) E. James Welsh of Carlsbad's Financial Commentator says that the ratio between median incomes and median home prices, normally 3 to 1, climbed to 4.5 to 1 during the bubble. It will be some time before it gets back to 3 to 1. "We're only about half way through the likely downward adjustment in home prices," says Welsh. Robert Campbell of the Campbell Real Estate Timing Letter keeps a Real Estate Crash Index, a mix of San Diego statistics. It is a stunning minus 83. In the 1991-1992 downturn it only got half as low. Nationally, prices have only come down one-third as much as they must to get back to normal. "This is going to be a real estate crash of monumental proportions," says Campbell.