Year	% of total
1970	68.08192138434345
1971	68.58564232873768
1972	68.55794106685975
1973	68.11502452962121
1974	67.63229459946668
1975	67.1560144162797
1976	66.02812662100102
1977	65.75974903229121
1978	66.95398103135994
1979	68.34235597243493
1980	65.29846060903807
1981	64.08193640821463
1982	65.57421973069184
1983	67.3426424345934
1984	67.31691401536418
1985	66.08277336380316
1986	65.69662039876317
1987	64.85403171128623
1988	65.70632951128303
1989	65.9294090164245
1990	76.36195752539243
1991	75.19047619047619
1992	74.76145038167938
1993	74.29526994744387
1994	74.01425178147268
1995	73.5965746907707
1996	71.2666338097585
1997	70.23867510959572
1998	69.70128022759602
1999	70.22321428571429
2000	67.34022556390977
2001	67.05827067669173
2002	67.90739900136178
2003	69.24406047516199
2004	70.51334702258727
2005	69.67281879194631
2006	68.11655405405406
2007	77.30557964729691
2008	76.84240362811792