Year	% of total
1970	89.8960411634989
1971	89.20029441530957
1972	89.22697014941252
1973	88.84423764359063
1974	88.38494831034573
1975	88.47068243604636
1976	88.09387100989746
1977	87.13099241790306
1978	86.70708471730482
1979	87.38492297783264
1980	86.30956116211883
1981	85.92602224789232
1982	86.49029883463668
1983	85.31202917438591
1984	85.01124412295566
1985	85.5006483152081
1986	85.09760212515685
1987	86.10673808691682
1988	87.60081358245391
1989	86.39682290665075
1990	90.9090909090909
1991	90.9090909090909
1992	83.33333333333334
1993	90.9090909090909
1994	90.9090909090909
1995	90
1996	80
1997	80
1998	81.81818181818183
1999	90.9090909090909
2000	81.81818181818183
2001	81.81818181818183
2002	88.88888888888889
2003	91.66666666666666
2004	83.33333333333334
2005	78.57142857142857
2006	76.92307692307693
2007	78.57142857142857
2008	84.61538461538461