Year Percent of GDP 2004-01-01 28.1722 2005-01-01 27.6561 2006-01-01 27.2819 2007-01-01 27.7419 2008-01-01 28.1349 2009-01-01 31.2309 2010-01-01 30.6641 2011-01-01 31.0063 2012-01-01 30.8039 2013-01-01 30.9227 2014-01-01 30.5783 2015-01-01 30.3119 2016-01-01 30.1844 2017-01-01 30.5367