http://www.bea.gov/iTable/index_regional.cfm
U.S. Department of Commerce. Bureau of Economic Analysis. Regional Data. Web. Accessed 19 April 2012, Data Year 2009. <http://www.bea.gov/iTable/index_regional.cfm>
http://www.bea.gov/iTable/index_regional.cfm
U.S. Department of Commerce. Bureau of Economic Analysis. Regional Data. Web. Accessed 19 April 2013, Data Year 2010. <http://www.bea.gov/iTable/index_regional.cfm>
http://www.bea.gov/iTable/index_regional.cfm
U.S. Department of Commerce. Bureau of Economic Analysis. Regional Data. Web. Accessed 19 April 2013, Data Year 2011. <http://www.bea.gov/iTable/index_regional.cfm>
U.S. Department of Commerce. Bureau of Economic Analysis. Regional Data. Web. Accessed 2 December 2013, Data Year 2012. <http://www.bea.gov/iTable/index_regional.cfm>