Year Percent of GDP 2004-01-01 16.7398 2005-01-01 18.6680 2006-01-01 21.1468 2007-01-01 25.0498 2008-01-01 25.9854 2009-01-01 30.2647 2010-01-01 33.7277 2011-01-01 35.6125 2012-01-01 38.0825 2013-01-01 37.7763 2014-01-01 39.1427 2015-01-01 38.5908 2016-01-01 36.3972