NEW YORK, NY — DECEMBER 20: Traders work on the floor of the New York Stock Exchange on December 20, 2011 in New York City. Following news of strength in the U.S. housing market and the easing of concerns about the European debt crisis, U.S. stocks rose today with the Dow Jones industrial average climbing 331 points, or 2.8 percent, according to early tallies. (Photo by Spencer Platt/Getty Images)