Year	% of total
1970	80.46143053530265
1971	84.92866174359438
1972	82.57992984310731
1973	84.68370117086312
1974	83.99894342582118
1975	82.23388378981127
1976	79.94035039628855
1977	83.1166945559316
1978	80.97688842028786
1979	79.74493677392825
1980	78.74065895370732
1981	80.11157028526006
1982	79.72910399110033
1983	79.40164679151067
1984	82.16264380996063
1985	81.36671158965319
1986	80.91465679179626
1987	78.04212220122375
1988	81.00720193942233
1989	81.33973263954792
1990	95
1991	95.38461538461539
1992	95.3125
1993	95.38461538461539
1994	93.75
1995	95.83333333333334
1996	94.5945945945946
1997	94.8051948051948
1998	94.8051948051948
1999	93.82716049382715
2000	93.5064935064935
2001	93.58974358974359
2002	93.82716049382715
2003	95.23809523809523
2004	94.6236559139785
2005	95.18072289156626
2006	94.04761904761905
2007	95.23809523809523
2008	95.55555555555556