Year	% of total
1970	11.826115985420865
1971	11.463209117561114
1972	11.020156439492672
1973	11.53854384073654
1974	11.711348414873658
1975	11.673374673114733
1976	11.73676892046597
1977	11.966543114977764
1978	11.873630284285474
1979	11.618410660046989
1980	11.398922278164452
1981	11.01860689792464
1982	10.976187406544287
1983	10.675632769021224
1984	10.270660058124523
1985	10.257360467203405
1986	10.470645618339436
1987	10.39977415719353
1988	12.134711275176818
1989	12.822720711704555
1990	26.745718050065875
1991	25.769230769230766
1992	21.902017291066283
1993	19.898819561551434
1994	16.114790286975715
1995	16.502463054187192
1996	20.77922077922078
1997	20.572916666666664
1998	20.82191780821918
1999	15.29745042492918
2000	16.480446927374302
2001	16.893732970027248
2002	19.623655913978492
2003	17.827298050139277
2004	18.20580474934037
2005	17.391304347826086
2006	16.577540106951872
2007	15.789473684210526
2008	14.910025706940875