Year	% of total
1970	14.20362352901106
1971	13.898168017187091
1972	14.024245374771297
1973	14.635066288516803
1974	15.39331644196262
1975	15.16134203535626
1976	15.418632272897954
1977	14.590570964921525
1978	14.083619701750663
1979	13.770663690379775
1980	13.84983206275741
1981	13.550121155560124
1982	11.832087835211427
1983	12.44571513019748
1984	12.658603944101356
1985	12.887371243796247
1986	12.882074411188746
1987	12.799667584208516
1988	11.904592622676113
1989	12.013281259559303
1990	3.3057851239669422
1991	3.968253968253968
1992	4.651162790697675
1993	5.263157894736842
1994	5.88235294117647
1995	5.369127516778524
1996	4.242424242424243
1997	3.3707865168539324
1998	3.1088082901554404
1999	2.4154589371980677
2000	1.809954751131222
2001	1.7777777777777777
2002	1.7391304347826086
2003	1.702127659574468
2004	1.6736401673640167
2005	1.639344262295082
2006	1.6
2007	1.968503937007874
2008	1.9230769230769231