Year	% of total
1992	19.355382884602886
1993	23.184900088484518
1994	25.531267695766495
1995	26.792515615854
1996	27.866324447474504
1997	25.121147565085284
1998	28.80347060040796
1999	29.278365505925358
2000	28.266074861807823
2001	28.373512087331328
2002	26.851490598911848
2003	29.67083559996207
2004	35.21806958322686
2005	34.409245653959935
2006	25.860757524245276
2007	26.084906647324264
2008	19.105938171843725
2009	22.20619753589276
2010	21.57766639713932
2011	21.8837998270149
2012	22.536365263184805
2013	22.605599368096392
2014	23.13344769871394