Is The U.S. A Currency Manipulator?

The U.S. dollar has depreciated by about 30% over the last 8 years, and during that time period U.S. exports as a share of GDP increased from about 9% in 2002 to 13.2% in mid-2008, and then fell through early 2009 as a result of the recession and a stronger dollar (see chart).  Since early 2009, the dollar's decline has continued, and exports as a share of GDP have been increasing. Is the U.S. guilty of manipulating its currency to increase exports? 

Note: The chart has been updated to reflect U.S. exports as share of GDP on a quarterly basis.  I previously divided quarterly exports by annual GDP, and have corrected the data and chart above.  Thanks to Scott Grannis.