Year % of GDP 1990 16.930006442958177 1991 16.10620454302864 1992 16.906904229674723 1993 16.825924387958647 1994 16.46564771676311 1995 16.372729342647997 1996 16.95716651872393 1997 17.686992993032447 1998 16.64149417588557 2009 21.39374545681865 2010 21.027062541665323 2011 20.26659235070123 2012 20.841703613254808 2013 21.17945552141702 2014 21.297095948355267 2015 21.426151456959044 2016 20.94048296199258 2017 20.89852260071119 2018 21.18559069781506