Year Percent of GDP 2004-01-01 15.8134 2005-01-01 17.6734 2006-01-01 16.7511 2007-01-01 18.7874 2008-01-01 17.8522 2009-01-01 18.2280 2010-01-01 17.1173 2011-01-01 18.9103 2012-01-01 16.0865 2013-01-01 14.4122 2014-01-01 18.8876 2015-01-01 18.0919 2016-01-01 18.9299