Year	% of total
1970	48.39658392355687
1971	49.0223177125034
1972	51.37690129103921
1973	53.59762233085148
1974	55.50862316917253
1975	38.595160646428425
1976	38.04167582738637
1977	38.75189454069841
1978	43.87697167607552
1979	48.02681897937578
1980	56.565724140438455
1981	55.0348396767492
1982	57.171225980604454
1983	54.42565467540321
1984	55.283221542038895
1985	58.268859030533385
1986	57.5241273591245
1987	58.16294546058563
1988	58.10001400070003
1989	57.927358372679194
1990	88.88888888888889
1991	89.28571428571429
1992	90
1993	90.625
1994	91.17647058823529
1995	91.42857142857143
1996	91.66666666666666
1997	89.1891891891892
1998	90
1999	90.2439024390244
2000	90
2001	90.69767441860465
2002	88.37209302325581
2003	88.37209302325581
2004	91.30434782608695
2005	90.19607843137256
2006	90.38461538461539
2007	88.67924528301887
2008	87.71929824561403