Year	% of total
1970	1.7173446670019619
1971	1.5904872374283896
1972	1.6378500429462368
1973	1.6647644408090423
1974	1.4955163735790138
1975	1.5389861103590887
1976	1.6585214724411317
1977	1.624547587053277
1978	1.6202821975311001
1979	1.6360872269732496
1980	1.6879271338178206
1981	1.4753296623014607
1982	1.488402473413611
1983	1.5572062411741556
1984	1.4175542605344345
1985	1.5067805068653957
1986	1.6064141399041616
1987	1.647655202246726
1988	1.9056415202442283
1989	3.5328359721803113
1990	3.259668508287293
1991	3.932151117964534
1992	4.30188679245283
1993	4.048892284186402
1994	4.553264604810996
1995	4.502973661852167
1996	5.4283290924512295
1997	5.825242718446602
1998	5.603864734299517
1999	5.25231719876416
2000	5.333333333333334
2001	5.2734375
2002	5.93311758360302
2003	5.97165991902834
2004	5.615942028985507
2005	4.351767905711696
2006	4.904904904904905
2007	5.483549351944168
2008	6.593406593406594