Year	% of total
1970	8.201227317610858
1971	7.958806571899929
1972	7.774914495447664
1973	7.553571186295223
1974	7.142458182078432
1975	6.9590654412891455
1976	8.232817319443637
1977	8.512233028888563
1978	8.527086840545348
1979	8.25810085478443
1980	8.159608075104567
1981	8.168220956199562
1982	8.15155587927654
1983	7.7448632850298775
1984	8.286495088361631
1985	8.765202588026858
1986	8.82298324641083
1987	8.965130385487527
1988	9.278669810801542
1989	14.216619764686985
1990	8.372093023255815
1991	9.013605442176871
1992	9.281961471103326
1993	9.63855421686747
1994	9.698996655518394
1995	9.731543624161073
1996	10.217755443886096
1997	10.333333333333334
1998	10.616438356164384
1999	10.445205479452055
2000	10.034013605442176
2001	11.03448275862069
2002	11.036789297658862
2003	11.538461538461538
2004	10.947712418300654
2005	9.320695102685624
2006	10.869565217391305
2007	10.372771474878444
2008	9.244992295839753