Year	% of GDP
1990	16.20308030148958
1991	15.480632311095393
1992	14.894788241510277
1993	14.572302061301679
1994	15.030932726507713
1995	14.243195780430598
1996	14.774607446737145
1997	14.76779681152587
1998	14.647929335258095
1999	12.790216936493534
2000	13.072272855978381
2001	13.95870175504316
2002	14.513859551165838
2003	14.569598190490908
2004	14.918767860718837
2005	16.1682153601762
2006	16.74114814963156
2007	17.40992882351585
2008	17.147398944711256
2009	17.87497852878844
2010	18.956795528299157
2011	18.449258172595364
2012	18.532847914061218
2013	18.59427801225591
2014	19.985154946111553
2015	19.69121604169304
2016	20.634547752511097
2017	21.340698993219217