Year	% of total
1970	77.90894946688354
1971	80.23699921369149
1972	81.41201824287074
1973	80.87670644138922
1974	80.96841768775543
1975	81.73138842103604
1976	80.81517571661104
1977	80.96435118085408
1978	80.20177393961123
1979	80.2568758534833
1980	79.81281125773633
1981	79.30354252758356
1982	78.75439907843035
1983	79.50956292830274
1984	78.85675763168912
1985	80.87218024064514
1986	80.60835297166761
1987	81.36693956593017
1988	80.25331931031256
1989	80.35878180628215
1990	91.09947643979058
1991	91.21951219512195
1992	90.5940594059406
1993	90.14778325123153
1994	89.90384615384616
1995	89.57345971563981
1996	89.59276018099548
1997	89.42731277533039
1998	88.88888888888889
1999	84.43396226415094
2000	80.75117370892019
2001	82.30088495575221
2002	84.58498023715416
2003	83.88429752066115
2004	85.1145038167939
2005	85.82375478927203
2006	86.28158844765343
2007	86.82432432432432
2008	86.64383561643835