Year	% of total
1970	85.2406937876863
1971	88.56180149238253
1972	88.15949591412458
1973	87.80363472256029
1974	88.59780001921465
1975	87.53653432032196
1976	87.98457387019688
1977	87.52852581652346
1978	87.4939506250769
1979	85.57088961130265
1980	86.54705341567863
1981	86.78666446633042
1982	85.55449476676309
1983	84.97528994232817
1984	85.66094206842843
1985	84.85034390165457
1986	84.4094690182805
1987	81.92630235805318
1988	82.92870966912342
1989	81.91844566925339
1990	91.58878504672897
1991	91.00992410974898
1992	90.63218390804599
1993	90.259009009009
1994	89.5368782161235
1995	89.17233560090703
1996	88.91402714932126
1997	88.53107344632768
1998	88.55255916345625
1999	88.13089295618414
2000	87.66124509254067
2001	86.37698179682913
2002	84.93490390576565
2003	85.23255813953489
2004	84.10041841004184
2005	85.25811601915912
2006	85.22789676002198
2007	86.2453531598513
2008	86.2561847168774