Year	% of total
1970	84.54562522970299
1971	87.67767680009337
1972	87.36699742894865
1973	86.9995591075591
1974	87.99765940649237
1975	86.89767796697096
1976	87.6517903344728
1977	86.80653413468947
1978	87.07225574410286
1979	85.10569127943126
1980	86.3636316984758
1981	87.2260779003575
1982	86.31843637976543
1983	86.03793351729684
1984	87.48516136381204
1985	87.16988616974602
1986	87.61182214544259
1987	85.59179840086246
1988	87.53354346632047
1989	86.82560215905518
1990	96.48058252427184
1991	96.2515114873035
1992	96.26955475330927
1993	96.05734767025089
1994	95.94755661501789
1995	95.85798816568047
1996	95.88235294117648
1997	95.64691656590084
1998	95.77960140679953
1999	95.64691656590084
2000	95.32828282828282
2001	95.02617801047121
2002	94.3884892086331
2003	94.84924623115577
2004	94.16666666666667
2005	95.01133786848072
2006	94.6341463414634
2007	94.83726150392818
2008	94.30992736077482