Year	% of total
1990	81.05127698531517
1991	74.12737689078438
1992	77.8227928388528
1993	78.27105073577856
1994	77.18587761149048
1995	76.8640510627956
1996	74.48571792543362
1997	77.13221448750292
1998	78.23251372209434
1999	78.27437076819955
2000	77.90850016127811
2001	77.78750801135969
2002	79.70875219616148
2003	79.50438780470289
2004	78.03952996236858
2005	77.03280172412465
2006	77.64003638042803
2007	79.65827107403284
2008	78.05160611705246
2009	76.12965426777457
2010	74.2949719561098
2011	74.63709827929327
2012	72.23776212423516
2013	71.30324628600363
2014	70.70366234212815