Year	% of total
1970	5.114112718123341
1971	4.581862438527881
1972	4.74114282822148
1973	4.818901048275427
1974	4.139149279022628
1975	4.761572169870065
1976	4.890833103782629
1977	4.562630849177722
1978	4.653173134446485
1979	4.781357542401593
1980	4.254776310708892
1981	3.8310462508604037
1982	4.014527302142771
1983	3.543706491147016
1984	3.3294046167508853
1985	3.4644278151671726
1986	3.7426066629370016
1987	3.877165218576442
1988	4.339769541347527
1989	4.452837163828595
1990	7.598039215686274
1991	8.251231527093596
1992	9.00900900900901
1993	8.875
1994	8.675263774912075
1995	8.314606741573034
1996	8.076514346439957
1997	8.241758241758241
1998	8.161044613710555
1999	7.894736842105263
2000	9.536082474226804
2001	9.466666666666667
2002	8.739076154806492
2003	9.94475138121547
2004	9.822646657571624
2005	8.46262341325811
2006	10.016420361247947
2007	12.021857923497267
2008	13.537906137184116