Year Percent of GDP 2004-01-01 12.9594 2005-01-01 13.3277 2006-01-01 13.3654 2007-01-01 14.5596 2008-01-01 16.3373 2009-01-01 18.0153 2010-01-01 17.8185 2011-01-01 18.1556 2012-01-01 19.4441 2013-01-01 19.7259 2014-01-01 20.0671 2015-01-01 20.1745 2016-01-01 20.5527 2017-01-01 21.5746