BY THE NUMBERS — 2.3: The projected percentage drop in all men’s underwear for 2009, from research company Mintel. In November, Mintel had forecasted a 2.6 percent sales growth. Why care? Because some leading economists (a certain Alan Greenspan) point to men’s underwear sales as an indicator of consumer confidence and economy stability. So goes the thinking: If men can’t even afford to replace their underwear, they’re really in trouble.