Year	% of total
1970	83.32092063090221
1971	85.78824119659515
1972	74.02410208181715
1973	83.82084609817277
1974	87.49696813314412
1975	87.61642537923655
1976	83.87952660461883
1977	85.70658316415948
1978	87.43489839125684
1979	87.4618609743483
1980	87.22617236659234
1981	86.16599609075875
1982	86.98358294529885
1983	89.59373290076842
1984	88.409264910184
1985	87.00969653207893
1986	84.01252053322874
1987	84.10911543725935
1988	83.29875230197563
1989	82.95776269078982
1990	93.04347826086956
1991	92.16589861751152
1992	92.96482412060301
1993	92.89617486338798
1994	93.16770186335404
1995	92.36641221374046
1996	90.625
1997	91.12903225806451
1998	91.47286821705426
1999	90.83969465648855
2000	90.97744360902256
2001	91.11111111111111
2002	90.4
2003	91.36690647482014
2004	90.57971014492753
2005	91.48936170212765
2006	90.20979020979021
2007	90.41095890410958
2008	89.93288590604027