Description:The Daily Digit today is 3.1%. The U.S. economy grew at an annual rate of 3.1% from late summer to early fall, according to the final reading of third-quarter gross domestic product. It is much faster than anyone expected. And the reason is that people simply spent more money than initially thought. Plus, state and local government expenditures added to growth for the first time in nearly three years. Also, exports looked better, helping to narrow the trade deficit.(0:47)