From a National Science Foundation Info Brief:
Research and development performed in the United States totaled $456.1 billion in 2013, according to new data from the National Center for Science and Engineering Statistics, National Science Foundation (NSF) (table 1). This is compared to $435.3 billion in 2012 (revised downward from an earlier estimate) and $427.8 billion in 2011. In 2008—just before the onset of the main economic effects of the national and international financial crisis and the Great Recession—U.S. R&D totaled $407.0 billion.
In 2013, U.S. total R&D increased by $20.7 billion over the 2012 level. This is on top of gains of $7.5 billion in 2012 and $19.6 billion in 2011—in contrast to the negligible changes in 2009 and 2010. Much of the increase in these most recent years has arisen from a return of sizable yearly increases in business R&D performance. (All amounts and calculations are in current dollars, unless otherwise noted.)