Year	% of total
1970	79.37157356119965
1971	77.89166347038969
1972	77.62815847729455
1973	75.52827916168981
1974	73.63926773688246
1975	70.39769277688889
1976	70.65272301575666
1977	68.42868242103637
1978	66.85300866823398
1979	68.68040523838359
1980	69.28660209106212
1981	67.20162244419012
1982	77.30455657585202
1983	72.63362726757686
1984	71.23162682052676
1985	72.2706528661711
1986	79.01561812450495
1987	81.31110389870578
1988	82.25505161318826
1989	83.1915204595419
1990	83.33333333333334
1991	100
1992	100
1993	100
1994	85.71428571428571
1995	88.88888888888889
1996	83.33333333333334
1997	85.71428571428571
1998	87.5
1999	88.88888888888889
2000	87.5
2001	87.5
2002	100
2003	87.5
2004	88.88888888888889
2005	88.88888888888889
2006	88.88888888888889
2007	88.88888888888889
2008	88.88888888888889