Year	% of total
1970	77.82773564618776
1971	78.64736127796283
1972	80.07413693817908
1973	80.25438571937504
1974	79.9964799078577
1975	79.09970112587821
1976	73.07383007300828
1977	70.7260804820971
1978	70.48038364865845
1979	69.26555603750982
1980	64.57918223128749
1981	69.26845054667571
1982	68.58347053517953
1983	44.991697079494294
1984	33.60087640337198
1985	34.86947991842489
1986	33.060615294117646
1987	33.498381363955204
1988	30.06858141672745
1989	33.849009987403484
1990	100
1991	100
1992	100
1993	100
1994	100
1995	100
1996	100
1997	100
1998	100
1999	100
2000	100
2001	100
2002	100
2003	100
2004	0
2005	0
2006	0
2007	0
2008	0