Year	% of total
1970	2.684297485899507
1971	2.5899227106812464
1972	2.90142328419301
1973	2.9040679200466095
1974	2.9675940937261327
1975	2.6279510080514896
1976	3.199879309585591
1977	4.1359282133368485
1978	4.370081276459403
1979	4.398908255602514
1980	4.5262510642323335
1981	4.191410057906212
1982	3.8398082248982175
1983	3.8715882936143657
1984	4.4094480486744105
1985	4.5363774364422405
1986	4.744371168692632
1987	4.41471775490406
1988	4.982479223802935
1989	5.550843048623612
1990	9.375
1991	12.121212121212121
1992	10.81081081081081
1993	10.81081081081081
1994	10.81081081081081
1995	10.81081081081081
1996	10.256410256410255
1997	13.513513513513514
1998	13.157894736842104
1999	13.157894736842104
2000	13.513513513513514
2001	12.82051282051282
2002	12.195121951219512
2003	14.634146341463413
2004	15
2005	16.216216216216218
2006	15.789473684210526
2007	18.421052631578945
2008	18.91891891891892