Year	% of total
1970	95.91439158351494
1971	95.69108808341807
1972	95.69569705791626
1973	95.44111739216076
1974	94.92152053047114
1975	95.22317565002845
1976	94.90007141478479
1977	95.16014701837508
1978	95.31374867427024
1979	95.02197825194912
1980	94.6911904563624
1981	94.7033258887178
1982	94.6172579591001
1983	94.25835171940032
1984	94.15545653285102
1985	94.19856339612032
1986	94.20423118808534
1987	94.3049363208908
1988	94.50096753847738
1989	94.35202665155307
1990	97.51098096632504
1991	97.07401032702238
1992	96.6796875
1993	97.07401032702238
1994	97.38461538461539
1995	97.30941704035875
1996	97.22627737226277
1997	97.14285714285714
1998	97.08879184861718
1999	96.9208211143695
2000	96.80696661828738
2001	96.87943262411348
2002	96.64335664335665
2003	96.53739612188366
2004	96.44808743169399
2005	96.5194109772423
2006	96.15384615384616
2007	95.73170731707317
2008	95.57926829268293