Year Percent of GDP 2004-01-01 3.4419 2005-01-01 6.2064 2006-01-01 6.5713 2007-01-01 8.4276 2008-01-01 7.2288 2009-01-01 9.3384 2010-01-01 9.8929 2011-01-01 12.8221 2012-01-01 16.5542 2013-01-01 17.8606 2014-01-01 17.8697 2015-01-01 17.6845