Year	% of total
1970	84.99140581723648
1971	84.84124688359587
1972	83.32046650028626
1973	82.02063694180183
1974	81.23163451211389
1975	80.13080749666489
1976	79.9798478288395
1977	79.32778947177576
1978	78.73361901948711
1979	79.65292955978111
1980	80.5341138869241
1981	80.27508394698981
1982	81.12304025277699
1983	79.64605608649006
1984	77.84572383639988
1985	76.38533347087066
1986	75.28382428417724
1987	74.86301655521191
1988	72.65743086213
1989	73.33724845543527
1990	87.8048780487805
1991	87.5
1992	87.17948717948718
1993	87.5
1994	87.17948717948718
1995	84.61538461538461
1996	87.5
1997	85.36585365853658
1998	83.33333333333334
1999	83.72093023255815
2000	83.33333333333334
2001	80
2002	80.48780487804879
2003	82.5
2004	80
2005	80
2006	80.95238095238095
2007	79.54545454545455
2008	81.81818181818183