Year	% of total
1970	2.760486496659452
1971	5.208379480402857
1972	5.042827846346051
1973	8.738821114216632
1974	9.777667629659732
1975	9.928119587187666
1976	11.284726501187304
1977	10.173926088772733
1978	10.359031135670115
1979	8.576474343627801
1980	9.642646971725044
1981	10.45185477881548
1982	9.885010794574553
1983	8.951717982734154
1984	12.002442886501532
1985	12.53653373398719
1986	10.259518367617343
1987	7.89212533318827
1988	9.797813023454866
1989	10.844898892179554
1990	77.5
1991	76.66666666666667
1992	75.83333333333333
1993	75.83333333333333
1994	75.63025210084034
1995	72.11538461538461
1996	71.76470588235294
1997	63.888888888888886
1998	53.44827586206896
1999	36.36363636363637
2000	10.344827586206897
2001	13.793103448275861
2002	12.5
2003	11.76470588235294
2004	10.256410256410255
2005	11.11111111111111
2006	10
2007	12.82051282051282
2008	11.363636363636363