Year	% of total
1970	41.66594282294873
1971	41.320959962823714
1972	38.98815100574619
1973	38.260582106848986
1974	36.1867074310798
1975	32.98503905763487
1976	33.75042247570062
1977	33.62254702271709
1978	35.34682902687303
1979	36.217196463234316
1980	36.98468424359125
1981	37.17422534155607
1982	35.49379711243174
1983	34.78584407816849
1984	34.72194570268445
1985	34.739189863045524
1986	36.66505406331118
1987	37.53007682458665
1988	38.2588565551442
1989	41.98311339763801
1990	2.898550724637681
1991	2.843601895734597
1992	2.7906976744186047
1993	2.28310502283105
1994	2.2522522522522523
1995	2.242152466367713
1996	2.232142857142857
1997	2.2222222222222223
1998	2.2123893805309733
1999	1.762114537444934
2000	1.7543859649122806
2001	1.7543859649122806
2002	1.3215859030837005
2003	1.3215859030837005
2004	1.3215859030837005
2005	1.3215859030837005
2006	0.881057268722467
2007	0.881057268722467
2008	0.8771929824561403