Year Percent of GDP 2004-01-01 15.4037 2005-01-01 16.8456 2006-01-01 16.7779 2007-01-01 20.2583 2008-01-01 25.1340 2009-01-01 24.3012 2010-01-01 24.9396 2011-01-01 25.6141 2012-01-01 26.8850 2013-01-01 29.8223 2014-01-01 32.4991 2015-01-01 35.4797 2016-01-01 34.1509 2017-01-01 35.5003