Year Percent of GDP 2004-01-01 16.1443 2005-01-01 17.1144 2006-01-01 25.6206 2007-01-01 30.0932 2008-01-01 29.4267 2009-01-01 31.0858 2010-01-01 31.6642 2011-01-01 29.4232 2012-01-01 28.9744 2013-01-01 31.9953 2014-01-01 29.5623 2015-01-01 31.3883