Year Percent of GDP 2004-01-01 17.1238 2005-01-01 17.1097 2006-01-01 17.9862 2007-01-01 20.2222 2008-01-01 20.0707 2009-01-01 20.3919 2010-01-01 22.7819 2011-01-01 28.2414 2012-01-01 26.1846 2013-01-01 26.2858 2014-01-01 27.9881 2015-01-01 31.8085 2016-01-01 31.1575