Year Percent of GDP 2008-01-01 15.8291 2009-01-01 16.4905 2010-01-01 17.1953 2011-01-01 16.8625 2012-01-01 17.0176 2013-01-01 15.9967 2014-01-01 16.9564 2015-01-01 17.2574 2016-01-01 15.0622