Year	% of total
1970	28.965544413116106
1971	29.00984160478961
1972	29.06731409041758
1973	29.160420433107486
1974	29.30385520190108
1975	29.5171559175262
1976	28.224581305852777
1977	27.341591537478422
1978	26.339465337732577
1979	26.20830269174792
1980	26.045481972349588
1981	24.22888682971619
1982	27.559237045095536
1983	25.853321890610882
1984	28.946451376049097
1985	31.470626926823087
1986	31.30088680307222
1987	28.712135938849876
1988	28.834427067359652
1989	35.35432876542069
1990	0
1991	0
1992	0
1993	0
1994	0
1995	0
1996	0
1997	0
1998	0
1999	100
2000	100
2001	100
2002	100
2003	100
2004	100
2005	100
2006	100
2007	100
2008	100