Year	% of total
1970	1.9325301410044242
1971	1.9031782134486142
1972	1.7751778509671068
1973	2.065994788829544
1974	2.2020209584426387
1975	2.216112970503594
1976	2.181759789242509
1977	2.179486642786997
1978	2.2587528518137714
1979	2.192916119801987
1980	2.3590016157890177
1981	1.9139977351839494
1982	1.5818448397846834
1983	1.233601633763102
1984	0.9656593301261245
1985	0.877465288658481
1986	0.878498399689745
1987	0.8892271052772663
1988	1.257190255968791
1989	1.1388150386084732
1990	3.4782608695652173
1991	3.686635944700461
1992	3.015075376884422
1993	2.185792349726776
1994	1.8633540372670807
1995	2.2900763358778624
1996	3.125
1997	3.225806451612903
1998	3.10077519379845
1999	3.0534351145038165
2000	3.007518796992481
2001	2.9629629629629632
2002	3.2
2003	3.597122302158273
2004	2.898550724637681
2005	2.8368794326241136
2006	3.4965034965034967
2007	4.10958904109589
2008	4.026845637583892