Year	% of total
1970	90.53788254491354
1971	89.54406926969531
1972	89.5806662808268
1973	88.8105978157101
1974	88.48059582239472
1975	88.1978262357208
1976	87.83343687931246
1977	88.0828774757781
1978	87.95221397870296
1979	87.87700524042845
1980	88.15375961742956
1981	88.69582049336451
1982	88.80480682382799
1983	89.9118606610088
1984	88.91118056184104
1985	89.47386767330285
1986	89.07546649291343
1987	87.56160675256002
1988	85.89328101926576
1989	84.85618202005271
1990	92.81437125748504
1991	92.98245614035088
1992	92.98245614035088
1993	92.85714285714286
1994	92.12121212121212
1995	92.20779220779221
1996	84.26966292134831
1997	84.69945355191257
1998	85.02673796791443
1999	82.73809523809523
2000	81.13207547169812
2001	79.05405405405406
2002	78.2312925170068
2003	79.87421383647799
2004	77.18120805369128
2005	77.56410256410257
2006	77.84810126582279
2007	78.44311377245509
2008	79.54545454545455