Year	% of total
1970	91.85598764981583
1971	91.39781128639898
1972	90.38426937125811
1973	89.79799054103682
1974	87.99743046773642
1975	87.77741635736966
1976	88.08094769561554
1977	88.1102622760574
1978	87.89131581037854
1979	87.81973340544063
1980	87.7346229451542
1981	88.10736136773343
1982	87.97458149831095
1983	86.4193124946444
1984	85.24467863568745
1985	85.51133843759847
1986	85.5066659643764
1987	85.43088961424627
1988	85.40335387603636
1989	85.56135672042929
1990	91.83168316831683
1991	91.19047619047619
1992	90.53398058252428
1993	90.1639344262295
1994	89.07363420427554
1995	88.67924528301887
1996	90.40178571428571
1997	92.11087420042644
1998	93.44262295081968
1999	94.95145631067962
2000	96.26168224299066
2001	96.12546125461255
2002	95.98540145985402
2003	96.06440071556351
2004	95.84086799276673
2005	95.90017825311944
2006	94.84536082474226
2007	93.44827586206897
2008	91.66666666666666