Year Percent of GDP 2004-01-01 4.7212 2005-01-01 7.7741 2006-01-01 10.1199 2007-01-01 13.2359 2008-01-01 15.6889 2009-01-01 16.2378 2010-01-01 18.6327 2011-01-01 17.6664 2012-01-01 18.2395 2013-01-01 17.3869 2014-01-01 18.5643 2015-01-01 18.8041 2016-01-01 20.0123 2017-01-01 21.5534