Year	% of total
1970	56.1166231706438
1971	60.67945113464028
1972	59.40401831374012
1973	62.09871197016026
1974	61.21403132006934
1975	60.31300429918879
1976	59.75608981224533
1977	64.14380350483133
1978	61.169142427318825
1979	61.0506214630869
1980	61.748783285823535
1981	62.9794291732973
1982	62.616646266283084
1983	61.88516508086905
1984	66.00666599791731
1985	65.9466904875228
1986	65.09778052604845
1987	63.543452955988776
1988	66.02602913680772
1989	66.64555523706021
1990	91.85664696500609
1991	90.4475737734326
1992	90.88495575221239
1993	90.15557476231633
1994	90.29411764705883
1995	90.72345390898484
1996	90.44052863436123
1997	90.90753277915844
1998	89.68523002421307
1999	89.663500241507
2000	89.31757897275139
2001	90.60748022425314
2002	90.14935988620199
2003	90.57520005471582
2004	89.54519359571347
2005	89.6256
2006	88.83853424834909
2007	93.01293669145679
2008	92.55547602004295