Year	% of total
1970	95.66098359241485
1971	95.525336440529
1972	95.5847416310987
1973	95.74062989172037
1974	95.9178097940825
1975	96.11984472611425
1976	95.82685668237556
1977	95.7602197130773
1978	95.75183534074117
1979	95.87516687437723
1980	96.20612891608212
1981	96.22645837235669
1982	96.15280511671838
1983	95.66317363931793
1984	95.38806669325696
1985	95.48596369145375
1986	95.46525403392218
1987	95.58444501348356
1988	95.71569673413697
1989	95.4608319831469
1990	91.55701754385966
1991	91.66666666666666
1992	91.87032418952619
1993	91.94404245055475
1994	91.77820267686424
1995	91.64265129682997
1996	91.79316888045541
1997	91.77489177489177
1998	91.63385826771653
1999	91.6015625
2000	91.24378109452736
2001	91.29353233830845
2002	91.60268714011515
2003	91.71348314606742
2004	91.84138559708296
2005	91.76843057440072
2006	91.99124726477024
2007	91.68900804289544
2008	91.77962396152164