Wall Street ends year with strong gains

US stocks closed out a year of double-digit gains and the S&P's best December since 1991 with a quiet and little changed session on Friday as investors found no reason to make big bets ahead of the new year. Improving economic indicators late in 2010 and stimulative measures from the US Federal Reserve propelled gains in the second half of the year, overcoming headwinds from Europe's sovereign debt crisis and continued high US unemployment.