WASHINGTON (AP) — The U.S. unemployment rate dropped below 8 percent for the first time since the month President Barack Obama took office, a surprising lift for both the economy and his re-election hopes in the final weeks of the campaign. The rate, the most-watched measure of the country's economic health, tumbled to 7.8 percent in September from 8.1 percent in August. It fell because a government survey of households found that 873,000 more people had jobs, the biggest jump since January 2003.